Not when your argument depends on that 90% number being correct. Some people might read that and say "wow really, 90%?" and that might actually persuade them. When you make a quantitative statement that has no backing its not up to you whether it stands on its own or not - if your numbers are not correct then it does not. You could say "some" instead of 90%, but you can't even say "most" without some kind of proof to back it up but you don't even do that, you just pick a really high number that would be very persuasive to anyone who doesn't question whether or not that number is true. Its lazy at best and intentionally misleading at worst.