human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Name, Year commissioned, Gross head (metres), Installed capacity (megawatts), Average annual output (million KWh)
###Question: 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?
gpt
SELECT MAX Year commissioned FROM table WHERE Gross head (metres) = 60 AND Average annual output (million KWh) < 59