The bottom line: Just under one person in five of the 34,000 tested though yesterday in the state are coming up positive, which roughly tracks national results to date.

More testing for the virus is needed to avoid risk of statistical error. Experts say that means about 10,000 tests a day, which Illinois still is only about halfway to achieving.

Nonetheless the data is a strong indication of the magnitude of the COVID-19 pandemic hitting Illinois and where it’s headed. It explains why Gov. J.B. Pritzker, Chicago Mayor Lori Lightfoot and other officials are so worried and have continued to stress their stay-at-home orders.

Asked if the state has any concern that the positive share is now nudging toward one in five, Pritzker spokeswoman Jordan Abudayyeh replied in an email, “Our team knew that as testing capacity increased we’d have more positives. Dr. (Ngozi) Ezike (head of IDPH) says we have to look at trends over weeks, not really day to day because of the lack of testing. So in a couple more weeks we’ll have even more complete data. We are still prioritizing certain people who get tests that are higher risk or presenting symptoms.”

Here are the figures, as reported to the Illinois Department of Public Health and released at my request by Pritzker’s office.

In the week of March 18 through March 23, an average of 1,426 tests a day were conducted by state labs or private labs that report to IDPH. An average of 196 a day came up positive, a rate of 13.74 percent.

The next week—March 25 through yesterday—testing ramped up significantly and the positive rate ticked up. Specifically, tests per day averaged 3,391, and positives per day averaged 637, or 18.8 percent.