Adjust auto leading for all paragraphs

Hi-

I want to increase my auto leading from 115% to 125% for all "Normal style"paragraphs in my document.

I know that I usually have to apply the paragraph style to the ones I want changed, but this document has hundreds of paragraphs, I can't do it manually.

I read in another post that the trick is to change the basic paragraph style and then have it as base for the ones I want to change.

I did that, but it does not affect anything other than the paragraphs that apply the styles to manually.

What can I do? Lars