T-SQL to find the SQL Server Installation date

Here is an handy T-SQL to find the installation date of SQL Server.

DECLARE @date AS VARCHAR(50), @ServerName AS VARCHAR(100)

SELECT @ServerName = CAST(SERVERPROPERTY('SERVERNAME') AS VARCHAR)

SELECT @date = convert(varchar(50),create_date,107) 
FROM sys.server_principals
WHERE name='NT AUTHORITY\SYSTEM'

PRINT 'This SQL Server Instance "' + @ServerName + '" was insalled on '+ @date