The Perseid Meteor shower?
I came regularly once a year, from '05 to '08,
The Perseid meteor shower comes regularly in mid-august, peaking around August 12 from 2005 to 2008
Barely staggered through the next couple of years,
In 2009 a Gibbous moon washed out most of the meteors and they were hard to see
Returned in 2010, and broke in 2011.
In 2011 there was a Full Moon which washed out the sky again, making the shower very faint
In '12 and '13 I was only half there,
But in '14 and '15 I was back like clockwork.
This year I didn't appear at all!
My theory kind of breaks down here, The dates don't really line up anymore.
If I'm right though, you will reappear