CREATE TABLE table_48583 ("Week" FLOAT, "Date" TEXT, "Opponent" TEXT, "Result" TEXT, "Attendance" FLOAT)

What was the Attendance on December 21, 1986 before Week 16?
SELECT SUM("Attendance") FROM table_48583 WHERE "Date" = 'december 21, 1986' AND "Week" < '16'
SELECT SUM("Attendance") FROM "table_48583" WHERE "Date" = 'december 21, 1986' AND "Week" < '16'