You can look at the linked page. It uses "Income in 2024 C-CPI-U (2000-2024) and R-CPI-U-RS (pre-2000) adjusted dollars." I would be interested in a dataset that shows deflated household income over this same period using a reasonable basket of goods. The FRED dataset shows an increase of roughly a third. It would take a very large adjustment to knock that down to significantly negative growth.