In the UK there were 6.3 million 999 calls (emergency ambulance calls) made in the last year.
(This is almost double the number of calls received 10 years ago. The number of immediately life-threatening incidents (termed Category A) was 1.8 million. A category A call is for those life-threatening conditions where the speed of response may be critical in saving life or improving the outcome for the patient, e.g. heart attack, serious bleeding, etc.)