Workers in seven of the 10 largest occupations typically earn less than $30,000 a year, according to the U.S. Bureau of Labor Statistics, CNNMoney reported. The nation's average annual pay is $45,790.


Food prep workers are the third most-common job, but have the lowest pay at $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 just $25,310 for the year.


Among the 10 most popular professions, only the nation's 2.6 million registered nurses earn a decent 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. Read more