CREATE TABLE table_13977 ("Country" TEXT, "Airport" TEXT, "City" TEXT, "2008" FLOAT, "Change  ( 08/07 ) " TEXT)

Which 2008 has an Airport of julius nyerere international airport?
SELECT AVG("2008") FROM table_13977 WHERE "Airport" = 'julius nyerere international airport'
SELECT AVG("2008") FROM "table_13977" WHERE "Airport" = 'julius nyerere international airport'