Not kept record.

       It was suspicion of this happening which called my/our  (Mike & me) to discover this bit of naughtiness.  
       Mike & I went out to find that that trickle was coming up through paving and not out of drain.
       I'll try and tag this so I can re-find it and see if it's once or twice per year.
       Just checked.  NO  guarantee I blip all, but last I have. was Aug last year.