I'm still recovering from my trip to CA, so all I have to offer this morning is this NYT Graphic depicting medal counts for all the Summer Olympic games of the modern era. Enjoy.
I noticed a couple things:
Communist countries like winning medals and are pretty good at it. Observe the East German and Soviet medal counts during the 60s and 70s. 1980 doesn't count because the US and some other countries boycotted, and neither does 1984 since the Soviet Union and some others boycotted.
The games have become more global since the early days. The number of countries winning medals has gone from less than two dozen in the 1920s and earlier to 87 during the 2008 games. Of course, the number of participating countries has increased since the early days, too.
There is/was a huge homefield advantage, at least in the early days. The first five Olympic games were dominated by the host country, until it was held in Belgium in 1916. Even then, Belgium went from 14th place in 1912 to 5th, and increased its medal count sixfold from 6 to 36.