The NTSB lists the airframe hours on about 75% of the homebuilt accidents. My Cessna 172 accident database shows about 82% of the accidents had aircraft hours.
Otherwise, the average GA aircraft is older and has a *lot* more time. The average time on the 172s was over 5,000 hours, while the homebuilts had an average of about 350. Wouldn't really be a fair comparison.
Here's a plot of aircraft time vs. number of homebuilt accidents over a 22-year period.
Ron Wanttaja