I'm not sure about the numbers but my company just recently had to shut down one of our trucks because they were not getting paid by the insurance. Now because of the other truck being shut down our crews are on runs on average of 22 of a 24 hour shift. This has caused a lot of people to quit the company which is causing a lot of people to have to work much more and I can see the people getting burnt out from it.
I work for a hospital -based service, and when we were a tax-supported entity , the equipment was much better , and the service did not have any problems getting any new help. Now that the hospital is a privately owned facility , most of our ambulances have190,000 to 290,000 miles on then and the shop has fits keeping up with the maintainence issues. we generally get 1 new truck per year but the new wears away due to not being able to rotate vehicles to a down status and doing preventative maintainence. the last year or two , we have managed to get all LP0 12's that had all the bels and whistles, and due to a large number of injuries, we have power-lift cots on all front-line trucks.