Prosper.com noted in it's September lending market survey that the occupations with the lowest defaults on Prosper are:

    1)   Computer Programmer  0.96%
    2)   Civil Service  1.48%
    3)   Analyst  1.63%
    4)   Mechanical Engineer  1.67%
    5)   Electrical Engineer  1.85%

Lowest default rates by state are:

    1)   Minnesota  0.00%
    2)   Ohio  0.65%
    3)   New Jersey  0.99%
    4)   Colorado  1.40%
    5)   New York  1.56%

Of these only for New Jersey and New York there is a obvious explanation – the average interest rates for loans in these states are low due to the state lending limits. This means in these states more loans with good credit grades were founded – reducing the risk.