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_191 ( id number, "title" text, "artist" text, "year" text, "location/gps coordinates" text, "material" text, "dimensions" text, "owner" text )

### Question ###
how many years after the george gordon meade memorial was built was the victims of communism memorial built ?

### Accurate SQL ###

SELECT (SELECT "year" FROM table_204_191 WHERE "title" = 'victims of communism memorial') - (SELECT "year" FROM table_204_191 WHERE "title" = 'george gordon meade memorial')