I see the Americans are being caught up in a juicing scandal.
Apparently their anti-doping agency has given a load of exemptions for asthma, way above the average population.
Liverpool FC had the same thing iirc. Something like >70% had therapeutic exemption for inhalers which apparently have no material benefit to performance....
However, juicing is probably rife. The number of athletes implicated in the BALCO thing was wild. I think they were mostly caught after the lid was blown of the whole thing.
There are a few world records that still stand from the 80s both in women's events. The 100&200M have stood since 88 (USA) and I think the long jump world record is held by the soviet union over the same period. I'd bet my bottom doller those women were juiced to the gills.