Americans are “moving on up” from one asset bracket to the next in record numbers, according to Spectrem Group’s Market Insights Report 2018.

The biggest gain was seen in the number of households with $1 million to $5 million in assets, not including their primary residence. Almost 600,000 households were added to this category during 2017 for a total of 9.98 million, a 6.2 percent gain year over year and the largest year-over-year growth reported by the segment since 2009. Sizable increases were also recorded across all other wealth segments.

In 2017, there were 31 million mass affluent households with a net worth between $100,000 and $1 million, an increase of 500,000 over 2016. The ultra-high-net-worth market, in which net worth is between $5 million and $25 million, grew to 1,348,000 households, an increase of 84,000 from 2016.

The wealthiest households, those with more than $25 million in assets, added 16,000 to their ranks for a total of 172,000, an increase of 10 percent, Spectrem said.

“The combination of record financial market performance and accelerating economic growth in 2017 have continued to increase the population of affluent Americans,” George H. Walper Jr., president of Spectrem Group, said in a statement. “It is particularly notable that the number of $25 million-plus households has grown by more than 10 percent in one year. There are now 55,000 more $25 million-plus households in 2017 than there were just five years earlier.”