In case you just have to know what % done you are - here
is a web site to calculate it for you!
It could be considered spoilerish because it lists all the dungeons, mini-games, and how many of some items there are to collect. However if you put in all the info about how far you are it will tell you what % done you are.
Man, geeks have a lot of spare time without that dating thing...
"You have completed 23.754666666667% of The Legend of Zelda Twilight Princess."