The president of the Central African Republic was recently ousted by rebel forces. According to atlanticwire there have been over 40 coups in the past 60 years. Do African nations have a higher propensity for coups?
I would say yes, that is a very unstable continent and coups very common:
Just for example the Guine Bissau experiences 3 coups in the last 10 years:2003,2009,2012: http://www.bbc.co.uk/news/world-africa-13443186
Coups are like business as usual in West Africa.