JSFiddle - React, Tailwind, and code Playground

JavaScript

function exponentage(percentage) {
    var year = 365.25*24*60*60*1000;
    var delta = (Math.pow(Math.E, (20.3444 * Math.pow(percentage,3) + 3)) -
Math.pow(Math.E,3));
    var now = (new Date()).getTime();
    return new Date(now - (delta * year));
}

for(var i = 0; i <= 1; i += 0.01) {
    document.writeln("<pre>");
    document.writeln(Math.round(i * 100) + ": " + exponentage(i));
}