The phrase "on average every day" is correct and commonly used in written English.
It is often used as an adverbial phrase to describe how often something typically happens. For example: "On average, I spend about two hours every day studying for my exams."
Data shows that about one person has been killed on average every day for the past three years by roaming tigers or rampaging elephants.
Ninety Americans are killed, on average, every day by guns.
Mail Online, with 2.5 million browsers on average every day, and 45.5 million browsers a month, is storming away – up 51.1% year on year.
That's how many pounds of coal each person in the United States consumes, on average, every day to keep the electricity flowing.
"Today's statistics show that overall absence is at a record low, with 70,000 more extra pupils in school on average every day in 2007-08 compared to 1996-97, proof the government's strategy is working.
A study by Brayden King, a professor at (aptly) the Kellogg School of Management, found that, during high-profile boycotts between 1990 and 2005, a company's stock price fell, on average, every day that the boycott was in the news.
Powell reckons that for 10 years he devoted some time to Northern Ireland "on average every other day or third day", and flew in and out at least once a month.
So far they've tested the product with 250 software developers, and claim that 70% come back regularly (on average every other day).
Another way to look at this region's future climate, the team notes: Extreme temperatures that are now seen only three times per summer, on average, will become normal and occur, on average, every other day in the summers between 2071 to 2100.
The PM10 sampling frequency was on average every 6th day, with each station operated on a distinct sampling schedule.
The researchers contacted the physicians on average every other day by phone, e-mail, or face to face, to fill out the documentation form if not yet done so.
