For more than 120 years, American workers have enjoyed a long Labor Day weekend to ring in the month of September. But not all labor is created equal, and more than a century after President Grover Cleveland officially acknowledged the first Monday of this month as a federal holiday, there's still a sizable gulf between the average earnings of demographic groups across the country.

The Bureau of Labor Statistics in August estimated U.S. workers' average hourly earnings clocked in at $25.73. Those working in the information sector – meaning folks like software developers, broadcasters and those in the motion picture and sound recording industries – brought in significantly more than that, with average hourly earnings hitting $36.77.

Meanwhile, those in the retail trade and leisure and hospitality industries account for a much larger percentage of America's overall workers, but make significantly less. Average hourly earnings of those in retail sat at $17.92 in August, while leisure and hospitality workers brought in just $14.39 per hour. These workers collectively account for nearly 70 percent of the country's lowest-wage earners.

The minimum wage in the U.S. has regularly made headlines in recent months, as the Fight for $15 campaign has gathered steam, both major presidential candidates have indicated they'd be open to raising the federal minimum wage of $7.25 and leaders in California and New York have signed legislation that will gradually bring their respective state-regulated minimum wages up to $15 per hour over the course of the next several years.

Minimum wage hikes have typically generated a mixed response, in part because there's little agreement on what they'd actually do to the overall economy. Some research suggests raising the minimum wage would cause employers to pull back on hiring, effectively slashing some middle-class and lower-wage job opportunities in the process. Conservatives historically have been more likely to cite these arguments and ultimately oppose efforts to raise minimum pay.

For example, a research fellow at The Heritage Foundation, a conservative think tank, recently stated that a $15 minimum wage in each state would bring about the loss of roughly 9 million jobs, with "states with lower living costs" like Georgia experiencing "relatively greater job losses."

Others, however, suggest these concerns are overblown and that a minimum wage hike would only be helpful to American workers. More than 600 economists – including seven Nobel laureates – in 2014 signed a letter to President Barack Obama advocating for a federal minimum wage increase to $10.10 per hour, arguing that "increases in the minimum wage have had little or no negative effect on the employment of minimum wage workers, even during times of weakness in the labor market."

At the time, the group predicted nearly 17 million Americans would see higher wages by 2016 if the federal minimum was boosted to $10.10, while another 11 million workers "whose wages are just above the new minimum" would see "a wage increase through 'spillover' effects."

Regardless of a raised minimum's potential effect on overall employment, it's clear that such a move would boost pay for millions of Americans across the country. The BLS in 2015 estimated 2.6 million Americans were paid at or below the minimum wage. About 45 percent of this group was between the ages of 16 and 24, while only 9.3 percent were at least 55 years old.

About 45 percent of America's wage and salary earners who make the minimum wage or less are under the age of 25. Andrew Soergel for USN&WR; Source: BLS

Those without a high school diploma are statistically more likely to be paid at or below the minimum wage, and instances of such pay tend to drop as educational attainment rises. More than 6 percent of workers in states like Arkansas, Louisiana and Mississippi brought in earnings at or below the minimum wage in 2015.

The geographic South has a higher concentration of minimum wage earners than the rest of the country. Ethan Rosenberg for USN&WR; Source: BLS

African-Americans are the most likely minimum wage-earning demographic by racial group, although it's worth noting there were nearly four times as many white Americans working at or below the minimum wage in 2015 as there were African-Americans, according to the BLS.

And women are actually significantly more likely than men to earn the minimum wage. A study put out last month by the National Women's Law Center stated that women make up "nearly two-thirds of minimum wage workers across the country." In states like Alaska, Oklahoma and New Hampshire, more than 70 percent of minimum wage earners are women.

The study also estimates women account for two-thirds of all tipped workers, like restaurant servers. These individuals often aren't paid the minimum wage because of the tips they bring in, so their guaranteed pay is often less than what someone would make earning $7.25 per hour.