GNP is not a sufficient measure, without knowing what percentage of it was spent on health. I think health expenditure in the USA is of the order of 20-times higher than in Cuba, per head of population - but wasn't able to verify it in time. Apologies for this, though I believe the GNP data alone makes it clear enough why the question is pertinent.
Source of data on GNP was http://www.teleport.com/~pbc/cuba/ch.htm
Charles Medawar