Direct combat is experienced by about 20% of the fielded forces. If you are in the designated combat zone, you receive a pay allowance for it, called combat pay. I served from 1977 to 1997 and with the exception of Desert Storm, did not serve in a combat period. During Desert Storm, I was off the coast of Columbia doing counter-drug-ops. If you add in the war on drugs, it's a bigger number. Same with the Cold War. They also serve who only stand and wait.