Trucking comes out on top for sheer number of unfilled openings. An average of 242,000 openings were posted on job boards per month between January 2013 and August 2014, while only 132,000 openings on average, or 54%, were filled per month, at a median wage of about $18 per hour, according to EMSI and CareerBuilder. While jobs are filled on a rolling basis and sometimes with a long lag time, the data offers a rough proxy for worker shortages.

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