CREATE TABLE table_43599 ("Name" TEXT, "Hanzi" TEXT, "Hanyu Pinyin" TEXT, "Population  ( 2004 est. ) " TEXT, "Area  ( km\\u00b2 ) " TEXT, "Density  ( /km\\u00b2 ) " TEXT)

What is the density of ?
SELECT "Density (/km\u00b2)" FROM table_43599 WHERE "Hanzi" = '昌黎县'
SELECT "Density (/km\u00b2)" FROM "table_43599" WHERE "Hanzi" = '昌黎县'