question: What was the population density of San Diego in 2009 ?
answer: 3,771.9 people per square mile ( 1,456.4 / km2 )
turker_answer: The population density of San Diego in 2009 was 3,771.9 people per square mile ( 1,456.4 / km2 ) .
rule-based: The population density of San Diego in 2009 was 3,771.9 people per square mile ( 1,456.4 / km2 ) .