Write SQL query to solve given problem: What is the percentage whereby the away team scored 2 goals during the 2017 seasons?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN FTAG = 2 THEN 1 ELSE 0 END) / COUNT(FTAG) AS REAL) * 100 FROM matchs WHERE season = 2017