C# Interactive quiz challenge, how do i create a grade percentage aside from just showing the # of correct answers.

using System;

namespace Interactive.Quiz
{

  class Program 
  {
    static void Main() 
    {
      var correctAnswers = 0;
      var totalQuestions = 5;

      Console.WriteLine ("Welcome to Mark's Interactive Quiz!");
      Console.WriteLine ("To begin with, please input your name.");
      var userName = Console.ReadLine ();
      Console.WriteLine ("Hello, " + userName + ". May the odds be in your favor.");

      Console.WriteLine (" Question #1 : ");
      var userAnswer1 = Console.ReadLine ();


      Console.WriteLine (" Question #2 : ");
      var userAnswer2 = Console.ReadLine ();


      Console.WriteLine (" Question #3 : ");
      var userAnswer3 = Console.ReadLine ();


      Console.WriteLine (" Question #4 : ");
      var userAnswer4 = Console.ReadLine ();


      Console.WriteLine (" Question #5 : ");
      var userAnswer5 = Console.ReadLine ();


      if (userAnswer1.ToLower () == "one")
      {
        correctAnswers ++;
      }
      if (userAnswer2.ToLower () == "two")
      {
        correctAnswers ++;
      }
      if (userAnswer3.ToLower () == "3" ||userAnswer3.ToLower () == "three" )
      {
        correctAnswers ++;
      }
      if (userAnswer4.ToLower () == "four")
      {
        correctAnswers ++;
      }
      if (userAnswer5.ToLower () == "five")
      {
        correctAnswers ++;
      }

      Console.WriteLine ("Your total correct answers: " + correctAnswers + ".");
      Console.WriteLine ("You got a grade of " + (correctAnswers/totalQuestions*100));


    }
  }
}