It depends what sort of table you are at. If you are at a very loose table then you will aim to win a very small number of very large pots at showdown.

If you are at a pretty tight table then you want to be stealing alot of small pots without a showdown (but getting out of the way when it looks like they have a hand).

I recon for the average 10NL table then about 55% Won $ at showdown works for me and the % won without showdown depends totally on the players im against.

Remember when using those stats that they are only counted for 1 session so they arent going to be a very reliable indicator of your expected value of W$SD. If you get good cards then you will win a higher % of hands and if you get bad cards you will win a lower %. The key is to make sure that when you do win a pot, it is a big as possible and when you lose, keep the pot small.