Text frequency analysis C#

source.cs

 var Alphabet = Enumerable.Range('А', 32).Select(x => (char)x).ToArray();
            string txt = Regex.Replace(text, "[#-.?!)(,: ]", "");
            txt = txt.ToUpper();
            Dictionary<char, double> Analysis = new Dictionary<char, double>();
            int count = 0;

            for (int i = 0; i < Alphabet.Length; i++) {
                count = 0;
                foreach (char letter in txt) {
                    if (letter == Alphabet[i]) 
                        count++;
                }
                if (count > 0) {
                    Analysis.Add(Alphabet[i], Math.Round(((double)count / txt.Length),2));
                }
            }