Since the COVID-19 vaccine became available in December, more than 41 million Americans have received their first dose, or 12.4 percent of the population, according to the CDC.

President Joe Biden promised to increase that number by 100 million people in his first 100 days in office, and he is on pace to do so.

According to federal data compiled by the CDC, 1.8 million vaccinations are given nationwide each day, and that number has increased steadily from when he first took office.

About 16.5 million COVID-19 doses were given between Dec. 14 and Jan. 20. In the month since then, more than 41 million vaccine doses have been administered.

“It’s very rewarding, very fulfilling, just to see the gratitude on everyone’s face, and the relief that they’re feeling,” said Stacey Rafteseth, a nurse at Denver Health.

She was one of the first people to receive their vaccine in Colorado in December and has since helped administer hundreds more.

“It just felt like a shot, but then, it’s just the thoughts afterwards that are like, ‘Oh, this is like a really big deal,’” said Erika Hiromitsu, who was vaccinated for the first time on Thursday. “It feels a little bit surreal, but I’m happy to be here.”

This past weekend, Rafteseth helped Denver Health vaccinate more than 1,000 local teachers, who recently got bumped up on the vaccine priority list.

“I don’t even know how to explain it. I mean to be a part of it, to help people,” she said. “I feel like every vaccination we get, we give to someone, is potentially one less person we see in the hospital as a patient later.”

CDC data shows that 16.1 million Americans have received both doses of their COVID-19 vaccine.