[greeneggs]

From that video:

"If we improve our detector sensitivity, by say a factor of two or three, the rates will go up from, you know, seeing one every month or every two months, to seeing one every day or every week."

- David Reitze, Executive director of LIGO

I don't know what their uptime is, but it sounds like they probably have a number of as-yet unreported observed events.