According to this article, "A 2007 survey for the Veterans Affairs Department of 1,941 combat veterans who left the military mostly in 2005 showed nearly 18 percent were unemployed as of last year. The average national jobless rate in October was 6.5 percent." This sounds about right, although it is probably higher.
I applied to hundreds of jobs when I left the Army. I had a good undergraduate degree, had begun a master's program, and still could not find a job. I was either "overqualified" or did not have the "experience" needed to do the job. One interviewer told me that all I had done in the Army was "manage a bunch of high school dropouts and some guns" during a lost war. Some employers feared that I had PTSD, because, afterall, all veterans apparently have PTSD.
This is a sad true story. Imagine what an injured veteran, with only a high school education, and a family to support goes through. I had it easy.