user: Question: What is the highest Population per km² (2009) that is in western province, with an Area (km²) larger than 5475?
Columns: ['Province', 'Capital', 'Area (km²)', 'Population census 1999', 'Population per km² (2009)', 'Population census 2009']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['Central Province', 'Tulagi', 615.0, 21577.0, 42.4, 26051.0]
SQL:

assistant: SELECT MAX("Population per km² (2009)") FROM "Table" WHERE "Province" = 'western province' AND "Area (km²)" > 5475.0;