Database: shooting
Question: Did the number of cases with Vehicle as subject weapon increase or decrease from year 2007 to 2008. State the difference.
SQL: SELECT SUM(IIF(STRFTIME('%Y', date) = '2007', 1, 0)) - SUM(IIF(STRFTIME('%Y', date) = '2008', 1, 0)) FROM incidents WHERE subject_weapon = 'Vehicle'