acid was a lot more prevalent when A/ the dead were touring and B/ a lot of the major chemists hadn't gotten busted yet. there was that nutty guy in the missile silo and some other old hippies, less publicized who got caught in the dragnet. some say it's all CIA made now. sounds conspiratorial but they did give us crack [and in the 70s, gave heroin to revolutionary black areas].
longwinded reply but yes, acid was abundant in the 90s.