Just Cause 2

I suggest completing all 7 agency missions first and carrying on your saved data onto mercenary mode* then go for 50.00%. Here's a list of "rough" percentages that are given for specific actions:

Sabotageing government property e.g. fuel tanks, gas pumps, generators etc = 00.01%

Collecting resourse items = 00.01%

Faction side missions = 00.20%

Faction items e.g. black boxes, skulls, drug drops = 00.03%

Races/Challenges = 00.10%

Assassinating colonels = 00.10%

Sabotageing rarer government property e.g. propaganda trailers, wind turbines, cranes etc = 00.01%

It took me about 31 hours to do this.
Remember you gain NO EXTRA percentage for completing areas only for collecting and destroying property within that area.

*Mercenary mode is is basically the same as normal mode except each time your percentage increases it shows up on the screen and when you look at the map.

Sorry if some of the actions are worth more or less than i stated, i can't be 100.00% sure. Bad pun lol.