=((A1-A$21)/($A$1-$A$21))*100
basically it is (value / minValue) / (maxValue - minValue) which will give you 1-0 and then multiply by 100 for 100-0
93.932110091.429897.09857488.181793.332390383.492787.895477778.288381.86095771.322273.783738765.493867.025687660.640461.398152754.978154.832695249.734248.752374144.412242.581495739.096636.418038234.635831.245724330.536226.492223226.441621.744519622.117516.730709919.031413.152365715.70489.2951609312.04095.046855549.3781.95921337.68830