63/66 as a percentage is 95.45%. This value shows that the fraction is very close to a whole, just a little short of 100 %.
The fraction 63/66 can be thought of as 63 parts out of 66 equal parts. Because the numerator is only three less than the denominator, the result is high, which is reflected in the percentage above.
You’ll see this kind of number when something is almost complete—like a test score of 63 correct answers out of 66 questions. It’s a quick way to understand how much of the total you have.