The US Centers for Disease Control and Prevention says half of the country's population has received at least one dose of a coronavirus vaccine.
Data presented by the CDC shows that more than 166 million residents, or 50.1 percent of the population, had received at least one shot as of Friday.
More than 133 million people, or 40.2 percent of the population, have been fully inoculated, including those who received the second dose of a vaccine requiring two shots.
By age group, 74.5 percent of people 65 or older have completed the required number of inoculations.
The number of new cases of the coronavirus in the US has declined as the vaccination rollout has progressed.
The average daily count of new cases in the seven-day period through Thursday was around 20,000. That's down from an average of about 250,000 at the peak of infections.
President Joe Biden has laid out a plan calling for 70 percent of residents aged 18 or older to have at least one shot by July 4.
In a speech on Friday, Biden said 10 states have already reached this milestone.
The government is now focusing on inoculations for young people and those reluctant to get the vaccine. Some states have unveiled several measures to encourage vaccinations, including a lottery with a one-million-dollar prize.