External factors such as being shagged at the end of the working week?
On average, the last couple of years have seen me do somewhere in the region of 650 per year.
Reasonably busy school, 5 days a week (including weekends). Not too many long days and a few nights thrown in.
Best month was about 80, worst was about 30.
So many factors to affect it though.
Tcheus.
Horst.