Not much of a trend that I can see. Although, there does seem to be a mild up-tick in biggies since fall '08, when the CERN large hadron collider went into operation. As you may remember:
...critics have argued, however, that Cern has ignored or downplayed the risk that the collider could produce a black hole that would swallow the Earth...
And of course an early sign of an Earth swallowing black hole would be massive earthquakes. Not that I believe it, but if the idea goes viral I want credit.