From which country does the most umpires are from? How many of them are from the mentioned country?

which country refers to Country_Id; most umpires refers to max(count(Umpire_Id))
SELECT T2.Country_Id, COUNT(T1.Umpire_Id) FROM Umpire AS T1 INNER JOIN Country AS T2 ON T2.Country_Id = T1.Umpire_Country GROUP BY T2.Country_Id ORDER BY COUNT(T1.Umpire_Id) DESC LIMIT 1