Table: nj_county_colleges
Columns: college
2007_headcount
2007_2008_credit_hours
county_population_18_yrs
penetration_in_terms_of_enrollment_per_1000_adults
in_county_tuition_per_credit_hour_fall_2009

Question: How much was the cost of in-county tuition per credit hour at the Gloucester College by the fall of 2009?
SQL: SELECT "in_county_tuition_per_credit_hour_fall_2009" FROM nj_county_colleges WHERE "college" = 'Gloucester'

Question: How much was the in-county tuition per credit hour at the Mercer College by the fall of 2009?
SQL: SELECT "in_county_tuition_per_credit_hour_fall_2009" FROM nj_county_colleges WHERE "college" = 'Mercer'

Question: What is the biggest number for county population 18 years+?
SQL: SELECT MAX("county_population_18_yrs") FROM nj_county_colleges