CREATE TABLE table_60533 ("Data" TEXT, "Headcount" FLOAT, "Percent of total" TEXT, "Less than $25 , 000" TEXT, "$25 , 000 to $40 , 000" TEXT, "$40 , 000 to $50 , 000" TEXT, "$50 , 000 to $60 , 000" TEXT, "$60 , 000 to $70 , 000" TEXT, "$70 , 000 to $80 , 000" TEXT, "More than $80 , 000" TEXT, "Mean" TEXT)

What's the sum of the headcounts that have an n/a value of $60k to $70K?
SELECT SUM("Headcount") FROM table_60533 WHERE "$60,000 to $70,000" = 'n/a'
SELECT SUM("Headcount") FROM "table_60533" WHERE "$60,000 to $70,000" = 'n/a'