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_name_55 ( enrollment INTEGER, team_nickname VARCHAR, founded VARCHAR )

### Question ###
what is the average enrollment when the team nickname is wolverines and founded is after 1817?

### Accurate SQL ###

SELECT AVG(enrollment) FROM table_name_55 WHERE team_nickname = "wolverines" AND founded > 1817