BeginPackage["Wikicode`Pumice`"]
Production::usage="Production[date] gives the annual world pumice production from the specified date."
Begin["`Private`"]
Production[from_Integer]:=Select[pumiceData["Production"],DateDifference[{from},#[[1]]] >= 0&]
pumiceData["Production"] =
MapAt[{Round@#} &, #, 1] & /@
Import["http://minerals.usgs.gov/ds/2005/140/ds140-pumic.xlsx"][[1,
52 ;; 115, {1, 8}]]
End[]
EndPackage[]
