CREATE TABLE table_1381 ("Year" FLOAT, "January" TEXT, "February" TEXT, "March" TEXT, "April" TEXT, "May" TEXT, "June" TEXT, "July" TEXT, "August" TEXT, "September" TEXT, "October" TEXT, "November" TEXT, "December" TEXT, "Annual Additions ( in millions ) " TEXT, "Average Monthly Additions ( in millions ) " TEXT)

What septembers are 17.1 in December?
SELECT "December" FROM table_1381 WHERE "September" = '17.1'
SELECT "December" FROM "table_1381" WHERE "September" = '17.1'