from before launch through landing, it's a wonder the loss rate wasn't higher. There are so many things that have to happen at the right time and under such extremes of energy, it's something of a miracle that any of them go right.

This entry from 1992 caught my eye:

OCTOBER: Columbia ejects the LAGEOS-II satellite, built by the Italian Space Agency and designed to observe Earth. However, private analysts say the mission's overall goals seem slight given the cost of each shuttle flight, estimated at up to $1 billion, and the chance of a catastrophic failure, put by NASA at 1 in 78.

Based on 2 losses out of 113 missions, the rate to date is 1 in 56.5. That isn't all that far from the NASA estimate. I read recently that NASA believed the chance of a catastrophic failure was 1 in 240. We can only wish it was that good.