Percent means per hundred. One percent is one part out of 100, where 100 is the whole. If a room contained 100 people then 1 percent would be one person.
A percent is a way of counting part of a total and is comparable to a fraction or decimal. Fifty percent is the same as one half or 0.5. Percentages are often used to show an increase or decrease in value or to quantify a change in value over a period of time. As percentages use a common baseline, they are useful when comparing data with different totals or of a different size.