Hi maths & stats lovers of DiS.

I really need some help with something I am a bit stuck on.

I am trying to present some trending data of figures from the last few years. I want to be able to take the top items that have experienced the most overall growth through the last few years, then display a nice line chart of how they have got to where they are.

Is it possible to produce one figure that represents the overall growth (increase or decrease) over time that I can sort this stuff by?

A percentage difference from 2010 - 2013 won't do. % diff from 12-13 might be ok, but not ideal. I tried a Variance formula, but I am not sure the numbers are correct, unless I misunderstand what it means (which I think I might - deviation from the mean? I don't think I actually want that)

This is a bit of a very seriose VERY boring question, to which I hope one of you has an answer to. I know there are some Excel wizards amongst you.

please help. thank you.