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_50 ( win_average INTEGER, races_ridden VARCHAR, nationality VARCHAR, name VARCHAR )

### Question ###
What is the average win as a percentage of German racer Rudi Altig, who has ridden in over 79 races?

### Accurate SQL ###

SELECT AVG(win_average) FROM table_name_50 WHERE nationality = "german" AND name = "rudi altig" AND races_ridden > 79