user: Question: What is the mid-2010 to mid-2011 change where the July 1, 2011 density is 508?
Columns: ['Rank', 'County', 'State', 'Land area (km²)', 'Land area (mi²)', 'April 1, 2010 census', 'April 1, 2010 density (/km²)', 'April 1, 2010 density (/mi²)', 'July 1, 2010 official estimate', 'July 1, 2010 density (/km²)', 'July 1, 2010 density (/mi²)', 'July 1, 2011 official estimate', 'July 1, 2011 density (/km²)', 'July 1, 2011 density (/mi²)', 'Mid-2010 to mid-2011 change (Absolute)', 'Mid-2010 to mid-2011 change (%)', 'County seat or courthouse']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Los Angeles County', 'California', '10,509.87', '4,057.88', '9,818,605', '934', '2,420', '9,826,773', '935', '2,422', '9,889,056', '941', '2,437', '62,283', '0.63', 'Los Angeles']
SQL:

assistant: SELECT "Mid-2010 to mid-2011 change (%)" FROM "Table" WHERE "July 1, 2011 density (/mi²)" = '508';