What is the 20 year for Sulfur Hexafluoride?
CREATE TABLE table_21350772_2 (gas_name VARCHAR)
SELECT 20 AS _yr FROM table_21350772_2 WHERE gas_name = "Sulfur hexafluoride"
### Context: CREATE TABLE table_21350772_2 (gas_name VARCHAR) ### Question: What is the 20 year for Sulfur Hexafluoride? ### Answer: SELECT 20 AS _yr FROM table_21350772_2 WHERE gas_name = "Sulfur hexafluoride"