....here's a link to a U.S. Navy flying safety magazine article (Nov-Dec 2006) addressing F-18 mishap causes, including G-LOC:
http://www.safetycenter.navy.mil/MED...the_Hornet.htm
[excerpt]
Human-aircrew errors comprise 80 percent of all {F-18} Hornet Class A mishaps.
The Navy’s Human Factors Analysis Classification System (HFACS) of accident causation defines the logical progression through which these errors can be traced and causal factors explained.
...To capture recent trends, Class A mishaps were researched using data from a six-year period, starting in FY2000.
Of 65 mishaps, 52 were caused primarily by aircrew.
...Physiological factors are most often a precondition for a mishap in HFACS; however, they realistically can be shown to be the root cause of many accidents. Gravity-induced loss of consciousness (GLOC) and hypoxia continue to kill Hornet pilots. Six Hornets were lost directly because of physiological factors: three to hypoxia, two to GLOC, and one with vertigo as a contributing cause.