I wanted to know how much the decay rate on Bounty was when you got high enough up there, so I turned on kill innocents and went on a rampage. I started slaughtering the helpless around Mournhold and pilfering their dead bodies. Guards around this town are few and multiple water features to escape to in case they do chase me, made it the perfect place to try this out. After getting a high enough bounty I would log out and check every hour, the amount of decay is about 1000g per hour.
This may be useful information for those who want to go on a killing spree before logging out, estimate the time you'll be back on by 1000g for each hour you'll be gone. I probably would put it at 1000 less so if you'll be back in 8 hours, try to stop around 7000g; by the time you return you're a upstanding citizen again and nobody to harass you for being a homicidal psychopath. Also a great way to get that achievement for killing friendly NPC's.