From the San Francisco Chronicle:

In San Francisco earlier this year, for instance, an income of $223,576 was necessary to purchase a $705,000 home, the median, or midpoint, at which half of sales are above and half are below, the report said.

An elementary school teacher in San Francisco makes about $53,478 a year, researchers found, up from $51,100 in 2003.

Home buyers in San Jose would need $185,521 to buy a median-priced $545,000 home.

It seems that an elementary school teacher in SF earns more than a new PhD graduate in London.