public static double AverageValue30Year(string cbtt, string pcode, int month1, int month2) { var t1 = HydrometDataUtility.T1Thirty; var t2 = HydrometDataUtility.T2Thirty; var s2 = new HydrometMonthlySeries(cbtt, pcode, HydrometHost.PNLinux); s2.Read(t1, t2); MonthDayRange rng = new MonthDayRange(month1, 1, month2, 1); var runoff2 = Math.AggregateAndSubset(StatisticalMethods.Sum, s2, rng, 10); //compute monthly average here... var rval = Math.Sum(runoff2) / runoff2.Count; return(rval); }