CREATE TABLE table_name_31 (first_year INTEGER, notes VARCHAR(255), final_year VARCHAR(255))
What is the average First year that has a Notes of replaced by us 12 when i-94 replaced us 12, and a Final year larger than 1961?
    
SQL: SELECT AVG(first_year) FROM table_name_31 WHERE notes = "replaced by us 12 when i-94 replaced us 12" AND final_year > 1961