user: Question: How many time is the population density (per km²) is 2.5?
Columns: ['Metropolitan ring', 'Localities', 'Total', 'Jews and others 1', 'Thereof: Jews', 'Arabs', 'Population density (per km²)', 'Annual Population growth rate']
Types: ['text', 'real', 'real', 'real', 'real', 'real', 'text', 'text']
Sample row: ['Core 2', 1.0, 187200.0, 184100.0, 164600.0, 3100.0, '2,220.6', '0.6%']
SQL:

assistant: SELECT COUNT("Localities") FROM "Table" WHERE "Population density (per km²)" = '2.5';