San Mateo County holds a population of over 700,000. More importantly, it holds the headquarters of Facebook. According to new government figures, the county earns more than anywhere else in America—$168,000 per year on average. Facebook employees have singlehandedly skewed the whole area.

The Wall Street Journal's Scott Thurm crunched new federal Bureau of Labor Statistics numbers from Q4 2012 and noticed a perfect matchup between a 107% increase in San Mateo County's weekly wages and Facebook's IPO. Even though the stock has been a turd so far, plenty of the social network's staff was able to cash in. Enough to elevate San Mateo far above Manhattan, which averages out at second place with a measly $110,000, and Santa Clara County, at $99,000 (yuck).

Thurm explains:

The county’s wage surge was included in a detailed report on employment and wages for each of the nation’s more than 3,000 counties, based on reports filed by employers. Within San Mateo County, the industry that most stands out is “computer systems design services.”

Facebook employees also exercised roughly 51 million stock options in the fourth quarter, which might have added $1 billion to the “wage” total.

The notion of a wealthiest county "on average" should do a terrific job of masking the vast majority of Californians (and Americans) who've seen zero benefit from these tech money mushroom clouds.