Sanctuary cities are extremely beneficial to the economy. According to University of California, Davis economist Giovanni Peri, states with higher populations of undocumented immigrants tend to have skilled workers who make more money and work more hours, resulting in increased productivity (2013). Higher wages lead to more money being put back into the economy because workers have more capital to spend. In addition, higher production rates means lower prices. This profound effect is a result of undocumented workers. Chief Actuary of the Social Security Administration (SSA), Stephen Gross, says the statistics in his department show that undocumented workers contribute nearly $15 billion every year to Social Security through their payroll taxes (2013). This means they are a huge contribution to financing the retirement of baby boom generation elders, a cost which is continuing to be a topic of debate and concern.