What did you use to make the chart above?

The first bike I had that I rode seriously had a triple and I just figured I needed it. My lowest gear was 28/32 (22") and I used it for one climb in particular. Then I started riding a road bike where the lowest gear was 42/28 (41") and when I was able to do that particular climb, I realized that maybe I could live without the triple. Now I ride a compact double where the lowest gear is 34/28 (32"), and I no longer care to have a triple. Mabye when I am older...