ly ▁messages ▁distributed ▁through ▁the ▁" Mont ana ▁List server ", ▁a ▁L IST SER V ▁that ▁provided ▁an ▁Electron ic ▁ma iling ▁list ▁service ▁from ▁June ▁ 2 , ▁ 1 9 9 8 ▁through ▁June ▁ 3 , ▁ 2 0 1 3 , ▁as ▁determined ▁from ▁an ▁archive ▁of ▁activity . ▁However , ▁the ▁count ▁of ▁message ▁prior ▁to ▁October ▁ 1 5 , ▁ 2 0 0 1 ▁are ▁not ▁available . ▁ ▁Red : ▁Number ▁of ▁year ly ▁messages ▁on ▁the ▁ 1 2 ▁most ▁active ▁Y ahoo ! ▁Gr oups ▁specific ▁to ▁Native ▁American ▁fl ute , ▁as ▁reported ▁by ▁Y ahoo !. ▁ ▁Blue : ▁Number ▁of ▁year ly ▁posts ▁and ▁comments ▁on ▁the ▁ 8 ▁most ▁active ▁public ▁groups ▁on ▁Facebook , ▁as ▁reported ▁by ▁Soci ograph . io . ▁ ▁The ▁chart ▁shows ▁an ▁average ▁ 3 9 % ▁annual ▁growth ▁rate ▁in ▁aggregate ▁activity ▁from ▁ 1 9 9 8 ▁( the ▁in ception ▁of ▁Y ahoo ! ▁Gr oups ) ▁through ▁ 2 0 1 5 . ▁However , ▁note ▁that ▁these ▁statistics ▁do ▁not ▁take ▁into ▁account ▁the ▁change ▁over ▁this ▁period ▁in ▁access ibility ▁to ▁the ▁Internet , ▁use ▁of ▁social ▁media ▁vs . ▁private ▁messages , ▁the ▁use ▁of ▁closed ▁and ▁secret ▁groups ▁on ▁Facebook , ▁and ▁other ▁conf ounding ▁factors . ▁Despite ▁these ▁limitations , ▁the ▁chart ▁does ▁indicate ▁a ▁substantial ▁rate ▁of ▁growth ▁in ▁activity ▁and ▁interest . ▁ ▁For ▁additional ▁statistics , ▁see ▁the ▁fl ute