Bloody Hell!

Marginal Revolution has some figures by Rudy Rumell on Democide, or murder by governments:

I have estimated it (the world's democide totoals for the 20th Century) to be 174,000,000 murdered, of which communist regimes murdered about 148,000,000. Also, compare this to combat dead. Communists overall have murdered four times those killed in combat, while globally the democide toll was over six times that number.

Read the article here.