AL R -
The headline issue about homeless ex-service personnel appears to be the pro rata percentage. However, drilling down through the statistics show that a significant number of them spent only a short time in the services - mainly Army - before proving to be unsuitable for a life in the Services, by being unfit for training, demonstrating poor discipline, VW during basic training, and so on. As discussed on this forum in the past, it is easy to categorise ex-Service personnel - but there are no equivalent labels for ex-bus drivers, ex teacher etc.
Clearly there are otherwise 'good' people who have had careers in the Services who do fall thorough the cracks - generally it seems through addition (primarily alcohol) or relationship breakups.
PTSD, previously regarded as evident with only a small percentage of homeless service personnel, is likely to rise in during the coming decades as a result of our involvment in Iraq and Afghanistan. Combat Stress notes that SP and ex SP who present PTSD symptons are typically in their 40s and the incident(s) that brought on acute or chronic PTSD was typically 10-15 years beforehand.