Frequency of letters

Write a query that returns letters and their frequencies in the string.
Expected input and output
"gamma" → "Letter g occurs 1 time(s), Letter a occurs 2 time(s), Letter m occurs 2 time(s)"
using System;
using System.Linq;

namespace CSharpExercises.Exercises.LINQ
{
    class FrequencyOfLettersTask
    {
        public static void Main()
        {
            string word = "abracadabra";

            var letters = word.GroupBy(x => x);

            foreach (var l in letters)
            {
                Console.Write($"Letter {l.Key} occurs {l.Count()} time(s), ");
                // Letter a occurs 5 time(s), Letter b occurs 2 time(s), Letter r occurs 2 time(s)
                // Letter r occurs 2 time(s), Letter c occurs 1 time(s), Letter d occurs 1 time(s)
            }
        }
    }
}