I have wonder a bit about that. A quick look provided no quick answer. The statistics are all over the place, and do not always include hard numbers. Although I found a reported 60% of cases dropped but even that has a cost of $18,000 per case. 90% of cases that go to trial are in favor of the defendant with an average cost of $100,000.
"According to the American Medical Association, defensive medicine increases health systems costs by between $84 and $151 billion each year" An incomplete rendering of potential case is in excess of 1,000,000, that would come to about $47 billion per year. Plus the savings on "Defensive Medicine". Resulting in between $131 to $198 billion per year at the low end.