[DrPhil]

Originally Posted by starang21

http://www.thefreedictionary.com/percentage

A proportion or share in relation to a whole; a part

http://www.thefreedictionary.com/rate

A measure of a part with respect to a whole; a proportion

Thefreedictionary is just reminding you that we express rates as percentages. Whether it means the same thing depends on what you're looking at/who you ask. The point is that the Census was reporting counts and percentages in that educational attainment data. It can be converted to rates if you wish.