How to find out how many times search terms are used on search engines?

[Ki99]

Hi, I was wonderinmg if anyone can tell me where I can find out how many times specific search terms are used, I know there is this facility on overture but I have been told this only covers searches through them despite them claiming otherwise. I am trying to figure out which key words I should use for the promotion of works website and this would be handy

cheers

:beer: