The 100 Percent Solution
If you are writing a technical or scientific paper, you would use the % sign. But in general or nonscientific writing, spell out the word percent. Except at the beginning of a sentence, percentages are usually expressed in numerals. You never want to begin a sentence with a numeral, so either rewrite so that doesn’t occur or spell out the number. Here are some good examples of correct usage:
- Fewer than 5 percent of readers buy books at an actual bookstore.
- With 90–95 percent of the work complete, we can relax.
- A 75 percent likelihood of winning is worth the effort.
- Her five-year certificate of deposit carries an interest rate of 5.9 percent.
- Only 20% of the ants were observed to react to the stimulus.
- The treatment resulted in a 20%–25% increase in reports of night blindness.
Percent, used as an adverb, is not interchangeable with the noun percentage (I know that 1 percent is a very small percentage). Note also that no space appears between the numeral and the symbol %.
That is such great help! I never could understand the difference. What about other numbers? What is the rule?
There are lots of rules about numbers, and we’ll be going over some of them in future posts! And you can always Google your questions and find answers based on Chicago Manual of Style for US writing.
A great help. I can never remember the ‘rules’ about numbers. Thank you!