If you consider the US (and other) wars/interventions of imperialism motivated by capitalism, the number easily exceeds 100 million.
http://maoistrebelnews.com/2012/03/16/1-6-billion-killed-by-...
http://maoistrebelnews.com/2012/03/16/1-6-billion-killed-by-...
Deaths are counted multiple times, cigarette related deaths worldwide are capitalism fault, children killed by hunger are capitalism fault (especially in North Korea), famine of 1932-33 is capitalism fault (this one is really fucked up, because it is exactly the opposite).