BeginPackage["Wikicode`Lead`"]
Production::usage="Production[date] gives the annual world lead production from the specified date."
Begin["`Private`"]
Production[from_Integer]:=Select[leadData["Production"],DateDifference[{from},#[[1]]] >= 0&]
leadData["Production"] =
MapAt[{Round@#} &, #, 1] & /@
Import["http://minerals.usgs.gov/ds/2005/140/ds140-lead.xlsx"][[1,
51 ;; 117, {1, 11}]]
End[]
EndPackage[]
