Of more than 200 top executives who responded to a a Grant Thornton survey, 53% expect their companies to increase employment levels in 2013.

That figure is down from 71% in 2012 and 61% in 2011, according to findings presented at Hart's Energy Capital Conference in Houston.

"The meteoric rise (in employment) is maybe starting to level off a bit in the energy industry," Brandon Cradeur, national energy transaction advisory services leader at the firm, told an audience at the event.

But