how many millions of americans have a gross yearly income of maybe 35k?
randomly chosen Montgomery county in Kansas:
The median income for a household in the county was $30,997, and the median income for a family was $38,516. Males had a median income of $29,745 versus $20,179 for females. The per capita income for the county was $16,421. About 9.20% of families and 12.60% of the population were below the poverty line, including 16.80% of those under age 18 and 10.90% of those age 65 or over.
randomly chosen Benton county in Washington:
The median income for a household in the county was $57,354 and the median income for a family was $69,834. Males had a median income of $57,496 versus $36,575 for females. The per capita income for the county was $27,161. About 9.3% of families and 12.7% of the population were below the poverty line, including 19.3% of those under age 18 and 6.1% of those age 65 or over.[13]
Medians don't work that way. Maybe you're thinking of the average.
The median for 45-55 year olds is much higher than the population overall. It’s the highest of any 10-year cohort, IIRC.