If you're interested in non-binned numbers, Business Insider summarized the BLS data [1] a couple years ago. Nationally, the most common occupations are retail and food service workers. You could argue that Amazon is going to put some significant portion of those out of work in the next 20 years.

Note that truck drivers are not in the top 10 chart even though the American Trucking Association estimates 3.5 million truck drivers in the US since BLS puts the number at about 1.7 million. I don't know where the discrepancy comes from.

[1] http://www.businessinsider.com/most-popular-jobs-in-america-...