If this is meant to be a representative sample of the US, the data doesn't pass the sniff test. They don't provide enough context to understand how else we should understand it.
The data here appear to come from salary surveys of working individuals. The US Census Bureau data appear to be reports of income from all sources for all persons, which appears to include children 14 and over, full-time students, disabled persons, retired persons, and other persons unlikely to be reporting a salary to Sequoia.
[1] https://fred.stlouisfed.org/series/MEPAINUSA672N
also, this report only covers a listed number of "departments" and leaves off many lower wage occupations. retail, child care, most unskilled labor, etc dont appear to be included in the Strategy, Sales, Design, Engineering, Leadership, etc.