Above is one simulation, for purposes of visualization, of what just 40 events in 7 years might look like, and this is a conservative number of events based on what has already been verified.   The upper chart also shows a constant increase in intensity of flashes, since the latest two verified flashes seem to be much more energetic than the first two.

Only 4 of the 40 flashes shown above have actually been verified.  Those are labeled in RED on the graph.  The other 36 flashes are a simulated estimate.

Energy amounts taken from Table 4 in:    http://www.aanda.org/articles/aa/pdf/2013/12/aa22216-13.pdf