Most of you lot seem to avoid emergencies!
I made at least two hundred 999 calls for ambulances during the decade or so I was in charge of first aid in a secondary school. (My record was five in aweek, three of which were on the same day!). As far as I can rember though, I only had to make just one 999 call to the police during my time at the school (and I can't recall requiring the fire brigade there).
During the four years I ran a railway station, I had to call about a dozen ambulances, with just one 999 call to the Fire Brigade. Emergency calls to the police were far more common though, both using the 999 number and the internal emergency number for BTP headquarters. I probably made around a hundred in total. (There were also a couple of 'immediate risk to life' emergency calls to the signaller).
Other than that, I've dialled 999 a few times to alert the police to traffic hazards (e.g. when fallen branches, just after a bend, were causing drivers to swerve into the path of oncoming traffic) and used the emergency phones on motorways to alert them to similar hazards (e.g. a 15' long aluminium ladder between lanes two and three on the M25!)
I've also called the police on 999 after seeing someone apparently breaking into a house and to several incidents in pubs I've worked in, as well as calling out the fire brigade to a warehouse fire.
I'm sure that there were a few more incidents, which don't immediately come to mind, too!