 analysi librari user circul requir thi studi concern circul statist help describ librari user circul requir some decis rule develop paramet aid determin number copi book held librari aid weed book librari's hold the decis rule circul requir user well librari oper describ the method data collect describ detail applic librari compar charg system cumul distribut function circul larg colleg librari public librari prepar plot circul data stack hold data thi data plot subdivid subject categori circul oper characterist prepar three librari 