func Change(before int, after int) float64 {
	return 100 * ((float64(after) - float64(before)) / float64(before))
}
Change - calculate the percent increase/decrease from two numbers.
ex. 60 is a 200.0% increase from 20
package percent
func Percent(percent int, all int) float64 {
	return ((float64(all) * float64(percent)) / float64(100))
}
func PercentFloat(percent float64, all float64) float64 {
	return ((float64(all) * float64(percent)) / float64(100))
}
func PercentOf(part int, total int) float64 {
	return (float64(part) * float64(100)) / float64(total)
}
func PercentOfFloat(part float64, total float64) float64 {
	return (float64(part) * float64(100)) / float64(total)
}