Ide doesn't look like he has very long left to live.
So how do you convert those numbers into human time?
According to volume 13, Ohba made a formula back when Light's lifespan was show (the OP pic), but he/she forgot it later on, and the lifespans shown after that are gibberish made by Obata.
divide by 365
Is it really? I mean, it would be neat for the fans to be able to figure out everyone's lifespans based on a formula, but Ohba was just trying to make a manga. He/she probably wasn't thinking about that kind of stuff.
Look at one of Mello's thugs
(I un-inverted it again)