Still, in 2009-10, instructional spending per pupil in those 31 districts dropped nearly 10% compared with what would have been spent had funding levels remained steady, the study said.

WSJ: Study Weighs Recession Toll

The study shows, however, that the trend has been steady ever since, with no period of leveling off.

FORBES: The Digital, Free Market Fall of America

Meanwhile, the overall number of start-ups has "held steady or even edged up since the recession, " according to the study.

WSJ: With New Technology, Start-Ups Go Lean