구구단 출력하면 9x9=81 밖에 안나옴..왜이럴까요

{
            for(int a = 2; a < 10; a++)
            {
                for(int b = 1; b < 10; b++)
                {
                     label1.Text = a.ToString() + "x" + b.ToString() + "=" + (a * b).ToString()+"\n";
                    
                }
               
            }
          
        }