Maths help: curves on log scales

[madd0ct0r]

Can anyone help me out with what sort of curve I need to achieve something that looks like this?

[Steel]

Not really without knowing what the x axis is, or having any other critical information such as what on earth "achieve" means in this context?

[madd0ct0r]

nah, it's ok, I solved it. It was part of a trio. I solved the first two as they were nice obvious shapes, even on a log scale, but it took me an hour or two to realise that the third graph was simply the remaining percentage after the first two were taken away.