CREATE TABLE table_name_75 (year_commissioned INTEGER, gross_head__metres_ VARCHAR(255), average_annual_output__million_kwh_ VARCHAR(255))
What is the Year commissioned of the power station with a Gross head of 60 metres and Average annual output of less than 59 million KWh?
    
SQL: SELECT MAX(year_commissioned) FROM table_name_75 WHERE gross_head__metres_ = 60 AND average_annual_output__million_kwh_ < 59