Population

The combined population of Rwanda and Burundi was about 13 million in 1994. However, many refugees fled Rwanda that year from the Rwandan genocide. 800,000 Tutsis were killed but, many Rwandese Tutsi returned from Uganda after the Hutu army was defeated in 1994 bringing the population of Tutsi back up to nearly 11 million.

References: 

The History Place
   1999 Genocide in the 20th Century: Rwanda 1994 800,000 Deaths.
          Electronic document, http://www.historyplace.com/worldhistory/
          genocide/rwanda.htm, accessed November 13, 2012.