Ahead of the Sunday, Sept. 19 deadline for most D.C. government workers to be fully vaccinated against COVID-19, 70% of the city’s workforce has self-reported as fully vaccinated, as of Wednesday, Sept. 15, according to D.C. Mayor Muriel Bowser’s office.

Bowser issued the vaccine mandate for city employees on Aug. 10, as COVID-19 cases surged. At the time, 54% of city employees had self-reported a fully vaccinated status.

The mandate applies to workers, contractors, interns, and people who receive grant money from the city — in total estimated at more than 35,000 people. Anyone who refuses a vaccine, or who submits a religious or medical exemption, will be required to undergo weekly testing, using self-testing kits provided by the city. Those that do not adhere to the testing requirement will face “adverse employment action,” per the mayor’s order.

It’s unclear whether the 16% increase in vaccinated employees over the past month indicates that more workers went to get their shots as a result of the mandate, or that more workers started reporting their already-vaccinated status to the city. Still, the rise in self-reported vaccinations falls in line with a pattern observed by other employers that handed down mandates. A month after United Airlines announced a mandate for workers, more than half of the airline’s unvaccinated staff reported getting their shot.

Following the full approval of the Pfizer vaccine by the U.S. Food and Drug Administration in late August, eight D.C. councilmembers asked the mayor for a full vaccine mandate for D.C. workers — one that would not allow for a weekly testing option, unless a religious or medical exemption is provided. This is the kind of mandate the city has given to health care workers, who will face losing their license if they do not get at least one dose of a vaccine by Sept. 30.

The ultimatum has sparked concern for some first responders in the city, who worry that the mandate will drastically reduce the number of firefighters. The city has struggled to increase vaccination rates in its fire department and police force in the past several months, although these groups were among the first D.C. residents to be offered their shots.

As of today, an estimated 67.9% of D.C. residents over the age of 12 are fully vaccinated.