如何计算本年度的每个月有多少天？

DECLARE @dbegin DATE = DATEADD(YEAR, DATEDIFF(YEAR, 0, GETDATE()), 0); --获取本年第一天
DECLARE @dend DATE = DATEADD(DAY, -1, DATEADD(YEAR, DATEDIFF(YEAR, 0, GETDATE()) + 1, 0)); --本年最后一天
WITH ctea (ddate)
AS (SELECT @dbegin AS ddate
    UNION ALL
    SELECT DATEADD(DAY, 1, ddate)
    FROM ctea
    WHERE ddate < @dend)
SELECT MONTH(ddate) AS imonth,
       COUNT(*) AS idays
FROM ctea
GROUP BY MONTH(ddate)
OPTION (MAXRECURSION 0);

如何计算本年度的每个月有多少天？