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_204_590 ( id number, "year" number, "division" number, "league" text, "regular season" text, "playoffs" text, "open cup" text, "avg. attendance" number )

### Question ###
what was the difference in average attendance between 2010 and 2001 ?

### Accurate SQL ###

SELECT ABS((SELECT "avg. attendance" FROM table_204_590 WHERE "year" = 2010) - (SELECT "avg. attendance" FROM table_204_590 WHERE "year" = 2001))