The rate at which New York State has been adding millionaires to its population in recent years has fallen below that of other large states, potentially costing the state billions in unrealized tax revenue, according to a new report from a nonpartisan fiscal watchdog group.

At the same time, California, Florida and Texas had large increases in the number of people with annual incomes of at least $1 million residing in their states, all adding them at a faster rate than New York did from 2010 to 2022. The millionaire population in New York nearly doubled over that same time period, but it more than tripled in those other states.

The report, published on Thursday by the Citizens Budget Commission, comes at a time when the topic of millionaires in New York City, the taxes they pay and broader concerns about income inequality and affordability have been the most prominent themes in the race for mayor.

“We have a debate about affordability, but we need to raise more revenue,” said Andrew Rein, the president of the Citizens Budget Commission, “and we can raise even more revenue if we have even more millionaires.”

There were about 70,000 people earning $1 million in New York State in 2022, with half of them living in New York City, according to the report.

Mr. Rein said the timing of the report’s release, about nine weeks before Election Day, had not been influenced by politics or any campaign. The group’s trustees and its executive committee include officials from some of the largest corporations in the city. He said the commission has tracked the composition of New York earners and the state’s competitiveness for decades.