Keyword Variations?

[mbase22]

Hi,

can anybody tell me if it is useful to optimize the following keyword in all 3 Versions?
As I know google separates the 2 words as if using a hyphen - so it would be the same as if just using a space between the words.
But if you search for the different Versions in google there are different SERPS for every of this versions? Not many users will search using a hyphen between the words I guess - butt I saw some few keywords tipped in with hyphen in my google analytics report. And I want to be on top

1. Piloten Ausbildung

2. Piloten-Ausbildung

3. Pilotenausbildung

thx!

[AdamThompson]

Google seems to indicate that Pilotenausbildung is the correct version and the others are misspellings. I would optimize for Pilotenausbildung, but also make sure you sprinkle the other two versions in a few times onto your page.