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_21481509_4 ( n INTEGER, r1b1c4__r_v69_ VARCHAR )

### Question ###
What is the largest n value for 55.6% r1b1c4 (r-v69)?

### Accurate SQL ###

SELECT MAX(n) FROM table_21481509_4 WHERE r1b1c4__r_v69_ = "55.6%"