Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the mid-2010 to mid-2011 change where the July 1, 2011 density is 508?

### Inputs:
table_name: table, 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']

### Response:
SELECT Mid-2010 to mid-2011 change (%) FROM table WHERE July 1, 2011 density (/mi²) = 508