Definition:Percentage

Definition
A percentage is a convenient way of expressing (usually) a fraction as an easily-grasped number by multiplying it by $100$ and appending the symbol $\%$ which means per cent.

As conventionally understood, the number being rendered as a percentage is between $0$ and $1$, thus determining the range of a percentage to be $0 \%$ to $100 \%$.

However in many contexts that range is frequently extended (in particular, in the field of rhetoric):
 * "I want every member of this team to give one hundred and ten percent."

Examples
$\dfrac 1 2$ as expressed in percentage form as $\dfrac 1 2 \times 100 = 50 \%$.

$1.2$ can be expressed in percentage form as $1.2 \times 100 = 120 \%$.

Linguistic note
Centum is Latin for $100$. So per cent merely means per hundred.

Thus, for example $68 \%$ can be read and interpreted as sixty eight per hundred.

That is, sixty eight out of 100, or $\dfrac {68} {100}$.