WASHINGTON — In a year marked by a thriving U.S. economy, Americans named the nation’s improving economic outlook as the single most important event to them personally during 2018, according to a new NBC News/Wall Street Journal poll. But a much darker theme also continued to permeate the American psyche: another year of deadly mass shootings.

According to the new poll, more than a third of American adults — 35 percent — said that mass shootings, like those at a Florida high school and a Pittsburgh synagogue this year, were either the first or second most important events of 2018. Nineteen percent named mass shootings as the single most important news event in their lives over the past year.

That’s compared with 33 percent who called the improving economy one of the top two most important events to them this year, with 25 percent calling it the single most significant event of 2018.

Other events that ranked either first or second on Americans' lists: The separations of migrant families and the number of immigrants seeking asylum at the southern border (28 percent total), natural disasters including recent hurricanes and fires (26 percent), a record number of women and people of color being elected to Congress (19 percent), tariff and trade negotiations with importers like China (20 percent), the Mueller investigation (12 percent) and the MeToo movement to expose sexual harassment (9 percent.)

The 2018 data comes after yet another grim drumbeat of gun violence in schools, places of worship, and watering holes throughout the year. After a shooter left 17 dead at Marjory Stoneman Douglas High School in Parkland, Florida, this February, surviving students launched a nationwide protest movement that included a series of high-profile demonstrations called the “March for Our Lives.” Other massacres included shootings at a California bar (13 dead), a Pittsburgh synagogue (11 dead) and a high school in Santa Fe (10 dead).

The finding also marks the second time in as many years that mass shootings were either the most dominant event or the second most dominant one for Americans during the calendar year. In 2017, a combined 39 percent of Americans named shootings — which in 2017 included the country’s deadliest ever, at a music festival in Las Vegas — as a top-two issue.

Both independents and Democrats were most likely to call the shootings one of the top-two most significant events in 2018, while Republicans were most likely to name the economy as a top issue.

The partisan differences are stark. While nearly half of Democrats — 46 percent — were most personally moved by gun violence-related events, just 24 percent of Republicans said the same. And while nearly two-thirds of Republicans — 63 percent — named the booming economy as a top issue, only eight percent of Democrats agreed.

Also ranking high on Democrats’ lists were the family separations at the border (37 percent calling it the first or second most important issue) and the Year of the Woman in the 2018 midterms (32 percent.)

Among Republicans, trade and tariffs ranked high as a top-two issue (34 percent), as did recent natural disasters (25 percent).

Overall, Americans had a better outlook on both the state of the country and their own personal lives during 2018 than in past years.

A combined 30 percent of Americans called 2018 either one of the best years for the country or an above average year, the highest share recorded since pollsters began asking the question in 1991. Still, 45 percent called 2018 below average or one of the worst years they remember.

And 35 percent overall said that 2018 was one of the best years or at least above average for them personally, up from 28 percent in 2015.

The poll of 900 adults was conducted Dec. 9-12, 2018. The margin of error is +/- 3.27 percentage points.