Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_60533 ( "Data" text, "Headcount" real, "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 )

### Question ###
What's the sum of the headcounts that have an n/a value of $60k to $70K?

### Accurate SQL ###

SELECT SUM("Headcount") FROM table_60533 WHERE "$60,000 to $70,000" = 'n/a'