CREATE TABLE table_25438 ("Administrative Region" TEXT, "Population  ( 2002 census data ) " FLOAT, "Surface km 2" FLOAT, "Main Rivers" TEXT, "Average annual rainfall  ( mm ) " TEXT, "Average annual runoff  ( mm ) " TEXT, "Per capita average annual renewable water resources m 3" FLOAT)

Name the annual rainfail for 2002 population being 493984
SELECT "Average annual rainfall (mm)" FROM table_25438 WHERE "Population (2002 census data)" = '493984'
SELECT "Average annual rainfall (mm)" FROM "table_25438" WHERE "Population (2002 census data)" = '493984'