[fencepost]

Based on my reading of that, a very significant majority.

From a quick read before I dash out the door, it looks like at most ~21% had surgery based on indefinite or vague symptoms. I'd say that there's a good chance that many or most of those cases should have received at the least other treatment before surgery and that some physicians started resorting to surgery too soon once that surgery became easier, cheaper and safer.

That still leaves the other 79%.