Unemployment rates for US biological and physical scientists remains low compared with rates for the general population, according to 2010 data from the US Bureau of Labor Statistics (BLS). In the Current Population Survey, a poll of 60,000 households conducted by the US Census Bureau, geoscientists and environmental scientists reported 2.2% unemployment; chemists and materials scientists 3.1%; medical scientists 4.1%; and biologists 4%. Rates for each occupation in 2009 were 4.6%, 4.5%, 4.2% and 3.5%, respectively. The average rate of joblessness for the general population in 2010 was 9.6%. Richard Freeman, an economist at Harvard University in Cambridge, Massachusetts, says scientists with doctorates are much more likely to be employed than are those with only bachelors' or masters' degrees.