This increase is likely attributed to an increase in home values.

A total of 8.8 million households bought homes in the two years preceding the most recent American Housing Survey (AHS). The survey, sponsored by the Department of Housing and Urban Development, is conducted by the Census Bureau every two years. The 8.8 million homebuyers are the highest tallied by any AHS since the Great Recession. There were 11.6 million identified in the 2005 AHS, but the number fell to a low of 6.8 million in 2011. It has been climbing since then to 7.3 million in 2013, and 7.9 million in 2015. The total is broken into two subsets, the 3.3 million who were first-time buyers and the 5.5 million trade-up buyers. While the total number of buyers is up from the 2015 survey, the gain is among trade-up buyers who likely benefited from the rise in home prices which provided an opportunity to build equity and "trade-up" to new homes. The share of first-time buyers ticked down from 39 percent in 2015 to 37 percent. The typical buyer was 40 years old, 32 for first timers and 47 for repeat buyers.

Source: National Association of Home Builders