This may be straying from the original question, but just to give you an idea of how hard it is to verify information of this nature.
Stories
To begin with, let's make a distinction between "wrecked" and just a car with what some people would consider a "story." For a lot of people, a story could be anything from a major, VIN-marked component replacement (of which there are multiple, non-documented examples I have first hand experience with, such as engine or transmission), or a car having had any paint work that was not performed at the factory during original production. If a car was completely repainted because it sat covered in corrosive contaminants for an extended period of time, to some, that's interchangeable with "wrecked." What about cars that had major components changed before being ultimately put back to stock?
If you want to go by paint work alone, the largest, most well-known service and repair business associated with the Ford GT estimates to have done paintwork on approximately 350 Ford GTs between 2006 and 2019. That alone is a number approaching 10% of the total production, out of a single location. There are at least 5 businesses who have engaged in regularly repainting/repairing (or having those actions done on their behalf by whoever would endeavor to try) Ford GTs outside of any normal Ford dealer process.
Do the math.
Physical Damage
The same business estimates to have repaired approximately 250 GTs that have had physical damage, while also estimating that those repairs were handled roughly 50% insurance claim, 50% cash payment. Please note the word roughly here. Loss of value on a damage history car can be significant, so the incentive is strong to handle certain repairs off the books, and therefore unrecorded. Over the years I have seen many GTs awaiting repair with their VIN plates taped over, as I am frequently at this business.
As the value of the cars and prices of replacement components (new or used) have increased or decreased, the incentive has strengthened at times such that a number of cars with 70-100k worth of physical damage have been repaired via undocumented cash payment. This makes assessing how many cars are "totaled" difficult, because "totaled" can either be a piece of paper representing a light hit on the wrong day or a clean title car that was flipped on it's roof at 60 mph on the right one.
For trivia's sake, you can basically say every single car in the company Ford GT fleet hit something at some point, some of them more than once, some of them really hard. I saw the last two cars left at DST that got sold and when I asked what the damage history was, it was so endless nobody really had an answer. I drove a pre-production car before release that famously ended up in an auto publication, having been put into a ditch by a woman I can't quite remember.
Re-repairs
Everyone is aware that there have been businesses with less than stellar track records having these cars "fixed." I say "having them fixed" because it's well known that a lot of that work gets outsourced to whoever will take it on. This leads to a vast, vast disparity in the quality of work you'll see on a "fixed" GT. I have seen "fixed" GTs that were flat out dangerous in their negligent attempts at repair. We can ballpark that the initially referenced shop has done a secondary major "re-repair" to at least a few dozen GTs.
Knowing that, one could probably surmise that between the fate of various auction GTs, and GTs that found their way to less-than-knowledgeable Ford franchises, there's a whole lot of GTs wandering around out there in very questionable "repaired" states. The evidence of Ford dealers who had GTs in for repair that ended up with more damage than they came in with is voluminous. Hell, we had a member have two different Ford dealers wreck his GT before a third contracted repair facility totaled it on the freeway for good. Is that car on the road again? Probably.
There are also undoubtedly some repaired GTs that just found really awesome repair shops that barely saw a GT and fixed it like new.
So in summary, back to the original question of how many have been wrecked or totaled:
1) It depends on your definitions
2) Either way, it's a lot
3) It will never effectively be tracked because of the inherent incentives associated with shielding the wrecking of an expensive car
Conversely, how many completely, totally unmolested GTs, never modded, never damaged, never painted are still out there?
1) A plentiful amount for people looking to buy one
2) Less than people believe
I largely agree with what Chip wrote (outside of the wrecks at officially sanctioned Forum events, because, unless I'm missing something, we've had 1 guy whack his car into a tire wall at the track, a dingbat donk his fascia onto a post, and one non-serious fender bender on the road in 14 years).
How this relates to people interested in GTs? It's just trivia for people that own them. It's strong endorsement for the notion that the only way to verify you are buying a clean GT is an effective PPI performed by a knowledgeable professional. You can ask about every single car that will ever be listed for sale, and regardless of what answers you receive, this remains true.
As for exports, just by nature of the reasons how and why cars end up in various global markets, you'll never figure that out either. The car was effectively sold in North America and then very lightly sprinkled in the EU. Some of the most voracious consumers of supercars live in markets where they were not imported officially/legally, and they don't care to make them visible. There are a lot more than the officially-exported 101 units floating around in Europe.
Lastly, I would say having an opinion and an internet connection in no way qualifies someone as a subject matter expert.