Follow this link (takes a while to load depending on your connection) to see Rwanda and the U.S. graphed in terms of: expected life expectancy and income over the past 50 years. Thanks to www.gapminder.org! You can change the axes if you wish.
Rwanda and the U.S.
You can see the drastic effect of what I presume to be HIV in the mid-80s on Rwanda's life expectancy and a small but not as much of an effect in the U.S.