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_203_586 ( id number, "#" number, "nation" text, "qualification tournament" text, "place in qt" number, "sailor" text )

### Question ###
what is the average number of sailors for each country during the worlds qualification tournament ?

### Accurate SQL ###

SELECT AVG("sailor") FROM table_203_586 WHERE NOT "place in qt" IS NULL