Color Saturation based on Fixed Number

Hi All, 

I have a bar graph that has color saturation settings based on the highest value in that column. See below. 

I would like to have the color saturation based off a fixed number, for example, 100%. I would like the closer the number is to 100% the redder it is and the lowerd the greener. Is this possible? I tried making a column that is all equal to 100% and use that, but then all the bars are red. Any suggestions?

color saturation