As more women have declared campaigns for top political offices, CNN collected data of declared female candidates for US Senate elections since 1990, as well as 2018 governors and US House data. Averages were calculated by state and by year, creating a ratio for every year and state of female candidates out of total candidates for general elections.

There's no doubt many more women are running for high office, and particularly this year. In 1970, there was just one female Senate candidate. Today, there are 49 to 54 women running, depending on whether and which third-party candidates you include. There are 394 women running for the House and 56 in governor's races (including third-party candidates), as of May 23.

That's a mostly pre-primary figure, and fewer women will appear on ballots in November. In 2016, a presidential election year, 19 women running for Senate appeared on the ballot in November -- less than 20% of the 108 candidates who were on Senate ballots on Election Day.

There are significantly more Democratic women (32) running for the Senate than Republican women (22) in 2018, which is a constant of recent history, except for a few small spikes, all before 1994. The last time there were more Republican than Democratic women running for Senate was in 1994, when five Republican women ran, compared with four Democrats.

In 2018, 107 women hold seats in Congress, 20% of the 535 members. Of these women, 78 are Democrats and 29 are Republicans. This is the largest number of women ever representing constituents on Capitol Hill.

How many of the 54 women currently running for Senate will make it through their primaries? Not all of them.

One hotly contested seat is the Senate race in Arizona, rated by CNN as a tossup for November. There are multiple women running for both the Republican and Democratic nominations in a primary on Aug. 28.

The closest race appears to be on the Republican side, where two of the three main candidates are women. The candidates include notorious former Maricopa County Sheriff Joe Arpaio, Rep. Martha McSally and Kelli Ward. The hope among some Republicans is that Arpaio and Ward will split the anti-establishment vote and open a path for McSally as a more moderate nominee.

The most likely Democratic candidate (three of the seven official candidates are women) is Rep. Kyrsten Sinema, who has the backing of Emily's List.

Arizona has never had a woman in the Senate, and McSally told CNN in April that it is about time.

"I think we need more women in office, for sure," she said. "On the Republican side, I think we have 22 women in the House. I'm the only female veteran woman Republican in the House. We need to represent the diversity of our country, right? The more women we can have running and winning, the better off we'll be." This quote was taken before Debbie Lesk of Arizona was elected, making it 23 Republican women in the House.

President Donald Trump won Arizona with 49% of the vote in 2016 and Democrats are hoping to make inroads in the state.

There are 33 seats being contested in the Senate and in nine of them, only men are currently running. So women could technically win 24 seats in 2018, but it's unlikely to happen. In nine of the seats where a woman is running, she would face a male incumbent. However, in 12 seats, a female incumbent senator will be running. Incumbents have real advantages. Only two of the races featuring female incumbents (Democrat-held seats in Missouri and North Dakota) are rated by CNN as tossups. Of the seats featuring male-only tickets, two (Democrat-held seats in Indiana and West Virginia) are rated by CNN as tossups.

But that does not leave too much space for new women to win. Only three seats (Arizona, Tennessee and Utah) are left in which there is no incumbent and women are in the running. There's a high likelihood of a woman winning in Arizona, where top candidates from both parties are women. There's a good chance a woman can win in Tennessee, where Rep. Marsha Blackburn is contesting for the GOP primary and likely to face off against former Democratic Gov. Phil Bredesen in November. But there is probably little chance for Democrat Jenny Hill to win the Utah Senate race against her most likely opponent, Mitt Romney.

Senate success rate

Women's rate of success has varied. In 2016, 32% of the women who were candidates for US Senate in the general election won their races. The greatest success for women came in 2012, when 55% of female candidates on the ballot on Election Day won Senate seats. This may have been coincidence, as it was also a year in which many female senators were up for re-election, but it was the year that senators such as Mazie Hirono, Elizabeth Warren, Deb Fischer, Heidi Heitkamp and Tammy Baldwin were first elected. All are running for re-election in November.

2018 has been speculated to be the next "year of the woman." The first "year of the woman" was 1992, when five women were elected to the Senate, including both senators from California, which became the first state to have both seats occupied by women. Two of those senators elected in 1992, Dianne Feinstein and Patty Murray, are still in office and Feinstein is seeking election to a fifth full term in 2018. Murray was re-elected in 2016.

In 1992, 18% of the candidates running for the Senate were women, and 19% were in 1994. That number took a dip until 2016, when 18% of candidates for Senate were women. Of the people declared in 2018, 22% are women, the highest percentage in the history of the US Senate.

Gubernatorial races

Gubernatorial races are showing a similar trend. Out of the 338 candidates who have already declared for 2018 governor's races, 58 are women -- 17%. That number was only 11% in 2016, 12% in 2014 and 9% in 2012.

According to the Center for American Women and Politics , 12% of current governors are women: four Republicans and two Democrats. Out of all statewide elected offices -- including governors, lieutenant governors and other statewide elected officials -- women hold 22% of the 312 seats.

One governor's race that has heated up is in Georgia, where the primary election occurred on Tuesday. Stacey Abrams emerged victorious over Stacey Evans. While a Democratic win in Georgia in November may be a stretch -- the state is rated "solid" or "likely" Republican by prediction sites -- if Abrams is victorious, she would be the first African-American female governor in the US.

States with the most and fewest female candidates

The five states that have had the highest percentages of female candidates running for Senate since 1994 are California, Washington, Maine, Hawaii and Maryland. The bottom five are Mississippi, Tennessee, South Dakota, Vermont and Ohio.

Each state was rated from 1-50 with the average percentage of women since 1990, according to CNN's analysis. For example, 17% of Arkansas' Senate candidates have been women, making that state 15th on the list for general election female candidates.

No woman has ever made it to the general election for Senate in the state of Mississippi. There is one woman declared in 2018 -- Omeria Scott -- but no reliable polling has been released to show that she will make it past the primary. A woman was appointed to fill out Thad Cochran's term in 2018 -- Cindy Hyde-Smith -- and she is the first ever female senator for the state. Even though she is temporarily filling the seat now, she is running in an open primary against Chris McDaniel , a former state senator with ties to the neo-Confederate movement. If no one gets 50% of the vote, there will be a runoff.

California has had strong female candidates throughout the history of its Senate races, including in 2016, when, because of the state's open primary, two Democratic women ran against each other in November. Kamala Harris won the race, but the prevalence of top female candidates there skews the data slightly -- as 100% of its candidates were women in both 2016 and 2012. Other states with all female candidates include Washington (1998), Maine (2014 and 2002), Hawaii (2012) and Louisiana (2002).

CNN recently profiled some of the women who were inspired to run in 2018. Many women have been impacted by what is called "the Trump effect," a rallying cry. Programs such as Emily's List and the nonpartisan organization VoteRunLead are training and recruiting women for Congress.

Erin Loos Cutraro, from the nonpartisan group She Should Run, said at the time it is important for women to be represented.

"The reality is, you want to have people who disagree with you at the table," Cutraro says. "You want to have people who think differently. Smart, effective people who think differently. Because at the end of the day, you're going to come out with the smartest policy."