New survey data released from the U.S. Census Bureau on Wednesday found that 51% of the estimated 226 million American adults who have yet to receive a COVID-19 vaccine said they “definitely” plan to get the shot, while another 26% indicated they “probably” would.

The data was collected by the Census Bureau from Jan. 6 through Jan. 18, as part of the federal agency’s efforts to measure how households are being affected during the pandemic. The Census Bureau invited more than a million households to complete the survey and received roughly 68,348 responses.

About 8% of adults reported they had already received the vaccine. Of the estimated 19 million Americans who said they received the shot, 95% said they had either received or planned to get all required doses.

But survey results showed there is still a significant portion of Americans who are unwilling to be vaccinated.

About 14% of unvaccinated adults said they would “probably not” get the vaccine, and another 10% said they would “definitely not.”

According to the Census Bureau, these results indicate that about a quarter of all unvaccinated adults are unlikely to receive a COVID-19 vaccine once it’s made available to them.