All 4? I imagine American occupation was "good" for employment while it was going on - providing a steady flow of income from soldiers and the military paying for goods and services while we were there.
The unemployment rate was pretty constant from 1992 to 2012. "20 years" in my previous comment was ambiguous, but I had meant the 20 years prior to 2012, not 20 years prior to today. Which, now that you mention it, is also a curious thing--the constancy even after the blockade was lifted.