public static decimal GetTax(decimal amount)
        {
              var taxTable = new []
                             {
                                 new {Lower=0m, Upper=5070m, Tax=0.10m},
                                 new {Lower=5070m, Upper=8660m, Tax=0.14m},
                                 new {Lower=8660m, Upper=14070m, Tax=0.23m},
                                 new {Lower=14070m, Upper=21240m, Tax=0.30m},
                                 new {Lower=21240m, Upper=40230m, Tax=0.33m},
                                 new {Lower=40230m, Upper=decimal.MaxValue, Tax=0.45m}
                             };
            return taxTable
                .Where(t => amount > t.Lower)
                .Sum(t => t.Tax * (amount > t.Upper ? t.Upper - t.Lower : amount - t.Lower));
        }