Good question - not sure,precisely - perhaps 10 to 15. Om at least a couple of occasions we started IVs to compensate for lost blood - one was a major amputation (arm). Direct pressure worked nearly always; a couple of times we did use pressure points.

One feature of my experience is a major amount of lag time between the injury and the arrival of responders. Even with prompt notification, the interval is likely to be an hour or more.

One point I would make is that, when space and weight are critical, don't bother carrying a specialized T. Use your bandanna and a stick.

Who has actually deployed a tourniquet?