The biggest single change in the 2019 edition of The Associated Press Stylebook is the nixing of the word percent in favor of the symbol that means the same thing.
There are exceptions to the new guidance — you don’t use the symbol 100% of the time. But percent is no longer the default.
The 2019 AP Stylebook, which debuted May 31, is used by news organizations nationwide and by countless marketing and public relations organizations. You read 
material written in AP Style every day. It’s not the only style guide out there, of course. Many publications rely on other guides, but AP has exceptional influence over what we read and write.
The embrace of the symbol instead of the written word is one of the most significant changes we’ve seen. Where lowercasing internet (which AP did in 2016) is an example of AP Stylebook following a trend and acknowledging the ubiquity of the small “i” spelling, adopting % does not seem to have come from popular demand.
The switch grew out of a suggestion at the 2018 annual conference of ACES: The Society for Editing. The Stylebook editors present updates and gather feedback each year at the ACES conference in the early spring. Stylebook Editor Paula Froke recalled that there was widespread agreement in the room that the symbol’s time had come.
“My later scan of usage indicated that indeed, the sign was far more widely used than I realized,” Froke wrote in an email. “I discussed with our team and all were in favor. I discussed with our business news staff, which is one of the biggest users, and they were strongly in favor. They tested on the wire for a week and it went well.”
Joining the $ symbol
Froke said AP likens it to the use of the $ sign. The symbol is the default when we talk about specific dollar amounts, and it’s the only symbol we regularly use that way. AP and the rest of us commonly use cents instead of ¢ and and instead of &. AP Stylebook likes No. for number, not #. We use the @ symbol for social media handles, but not generally in place of the word at.
Journalists and others have been writing out percent as long as they have been following AP Style, though those near retirement age may remember the word was per cent in the early 1970s. British and Canadian English still favor the two-word per cent.
Is AP Stylebook leading change rather than reflecting usage? Maybe. In edited text, use of the symbol vs. the word may depend on the subject matter. In financial or scientific context with heavy use of data, it’s common to see %. In marketing, the symbol may have more impact. In the humanities, though, the written word may be more likely. Searching the Google Books corpus shows both forms are used, and which one is more common depends on how the search is constructed.
But a general Google search for “19 percent” yields 4.5 million hits, while a search for “19%” returns 217 million. The symbol is even more likely in a Google News search.
AP’s new advice is close to that of the Publications Manual of the American Psychological Association: Use the symbol only when it’s preceded by a number. That doesn’t actually say don’t use the word, but it seems implied.
The Chicago Manual of Style has it both ways. It says use a numeral for percentages, but choose the word or the symbol based on the context: “In nontechnical contexts, the word percent is generally used; in scientific and statistical copy, the symbol % is more common.” (9.18)
The MLA (Modern Language Association) Handbook also offers a choice based on the type of document. In nonstatistical or nontechnical uses, the number and the word are written out, so you could say, “I am right at least four percent of the time.” In other cases, use the numeral and symbol.
The Yahoo! Style Guide, cutting edge when published in 2010, allows for either word or symbol, but makes two points in support of the symbol: it saves space and in a passage that contains more than one percentage, the symbol stands out, which makes it easier to spot for comparison.
Exceptions to the rule
AP makes an exception for percentages at the start of a sentence, where words are preferred (if rewriting is not the better option). Casual use also calls for the word rather than the symbol. Presumably, you could support about 75% of what the AP Stylebook has to say, or you could be behind it 110 percent. Or there is “a zero percent chance you won’t forget the new rule and spell our percent.”
AP’s entry also reminds us that percent and percentage point are not the same thing. For example, a tax increased from 6% to 7% would be a 1 percentage point increase and a 16.7% increase. There is unlikely to be confusion if someone writes a 1% increase with context, but 16.7% is more accurate and a more useful number for helping the reader understand how much revenue is involved. If something increased from 20% to 40%, it doesn’t go up 20%— it doubles, or increases 100%.
Some other points in the AP Stylebook entry on percent:
- For decimal amounts less than 1%, use a zero and a period: 0.4%.
- Use decimals not fractions with percentages.
- Use percentage, not percent, when the construction is not paired with a number.
- For a range of percentages, it’s acceptable to write “12% to 15%, 12%-15% and between 12% and 15%.”
Expressing percentages with the symbol will take some getting used to, but the dollar analogy is a good one. It seems wordy to write 4 dollars instead of $4. Writing 4 percent may soon seem as excessive.
