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_20506 ( "Region of USSR" text, "Number of families" real, "Number of people" real, "Average family size" text, "% of total deportees" text )

### Question ###
What is the total number of regions where the average family size is 2.8?

### Accurate SQL ###

SELECT COUNT("% of total deportees") FROM table_20506 WHERE "Average family size" = '2.8'