America's most common jobs come with lousy pay.

Workers in seven of the 10 largest occupations typically earn less than $30,000 a year, according to new data published Friday by the Bureau of Labor Statistics. That's a far cry from the nation's average annual pay of $45,790.

Food prep workers are the third most-common job in the U.S., but have the lowest pay, at a mere $18,720 a year for 2012. Cashiers and waiters are also popular professions, but the average pay at these jobs tallies up to less than $21,000 annually. There are 4.3 million retail sales workers out there, making them the most common job, but the position pays only $25,310 for the year.

Among the 10 most popular professions, only the nation's 2.6 million registered nurses earn a good living, bringing home nearly $68,000 a year on average. Another two of the most common jobs -- secretaries and customer service representatives -- have an average annual wage of about $33,000.

Wages have been in the spotlight this year as the debate over income inequality intensified. Middle-class Americans have been losing ground, as median household income dropped by more than $4,000 since 2000.

Part of this decline stems from a disappearance of middle-class jobs and an explosion of lower-paying ones. Some 58% of the jobs created during the recovery have been low-wage positions, according to a 2012 report by the National Employment Law Project. These low-wage jobs had a median hourly wage of $13.83 or less.

President Obama has been pushing to raise the federal minimum wage to $9 an hour, and several states are considering increasing their minimum wages.