About half of all attempted coups d'état fail

though coups against autocrats have sometimes led to democratization, more often they install a new set of autocratic elites and expose citizens to higher levels of repression.

The data, again from Powell and Thyne (2011), show that about half of all attempted coups fail. The likelihood of failure varies with time period: 48% of attempted coups failed during the Cold War and 63% after it. In any case, regime change rarely follows failed coups: 6% of failed coups were followed by democratization and 3% by the establishment of a new dictatorship. In summary, coups fail frequently, and when they do, regime change rarely follows.

From 1950 to 1989, 14% of successful coups against dictatorships led to democracy within two years, while 40% did so from 1990 to 2015.