Write SQL query to solve given problem: What is the ratio number of territories in Northern region and number territories in Western region?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(( SELECT COUNT(T1.TerritoryID) FROM Territories AS T1 INNER JOIN Region AS T2 ON T1.RegionID = T2.RegionID WHERE T2.RegionDescription = 'Northern' ) AS REAL) * 100 / ( SELECT COUNT(T1.TerritoryID) FROM Territories AS T1 INNER JOIN Region AS T2 ON T1.RegionID = T2.RegionID WHERE T2.RegionDescription = 'Westerns' ) AS Calu