I'd say that 90% number is probably about right. Maybe a bit on the low side if just considering World Tour level teams. I'd venture that every one of those teams has a program.
I've gotten to where I simply don't care about the doping drama anymore. I like racing and I'll keep watching.
These doping stories sell because people generally love drama. And the more drama that can be wrapped up around the periphery of racing, the more it keep people hooked into talking about it constantly.