At best it sounds like a paraphrase. Did people use terms based on percentages in those days. I would have thought they would have been more likely use use fractions.

I recall seeing the words "per centum" used in a sign posted in a general store from the Revolutionary era/early frontier era of America.

(The sign dealt with relative discounts from the face value of different kinds of currency...)

A little googling of my own produced this:

Thomas Jefferson on Politics and Government

Found this little gem there:

"The first principle of republicanism is that the lex majoris partis is the fundamental law of every society of individuals of equal rights; to consider the will of the society enounced by the majority of a single vote as sacred as if unanimous is the first of all lessons in importance, yet the last which is thoroughly learnt. This law once disregarded, no other remains but that of force, which ends necessarily in military despotism."
--Thomas Jefferson to Alexander von Humboldt, 1817. ME 15:127

I don't think that Jefferson ever referred to the American system as democracy, so he may have said that about democracy: but he always called the American system a republic. Evern more, he still attributed the same authority as Natural Law to the vote of the majority.

the "link insert" command did not work.

Here is the link where I found the above quote:

http://etext.lib.virginia.edu/jefferson/quotations/