Terry’s question: “I am wondering about the use of per cent and percentage. For instance, should it be ‘Early Development Instrument: Percent Vulnerable by Domain’ or should it be ‘Percentage Vulnerable by Domain’?”
BizWritingTip response: According to the AMA Manual of Style, deciding on whether to use per cent or percentage is simple. “The term percent and symbol % should be used with a specific number.” Percentage is used when there is no number.
He requested a ten per cent pay increase.
There was an 18% drop in the fan base.
By what percentage did the fan base drop?
A large percentage of the community was exposed to the flu.
Early Development Instrument: Percentage Vulnerable by Domain
At the beginning of the sentence, spell out both the number and the word percent.
Twenty-five percent of the people visiting hospital emergency rooms over Christmas had influenza.
The symbol % should be placed close to the number and should be repeated with each number.
Twenty-five per cent to 35% of people visiting hospital emergency rooms over Christmas had flu symptoms.
Better: Flu symptoms were reported in 25% to 35% of people visiting hospital emergency rooms over Christmas.
Many style books say that if you are using the symbol % always use the number – never the word – with it.
You only missed 5% of the movie.
Note: The Oxford Canadian Dictionary accepts both per cent and percent. I purposely used both variations in this BizWritingTip, but you should be consistent. Choose one style and stick to it.