Write SQL query to solve given problem: What percentage of countries in South Asia have the Life expectancy at birth, female (years) greater than 50?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN T2.value > 50 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.CountryCode) FROM Country AS T1 INNER JOIN Indicators AS T2 ON T1.CountryCode = T2.CountryCode WHERE T1.Region = 'South Asia' AND T2.IndicatorName = 'Life expectancy at birth, female (years)'