Below is a link to a calculator produced by ESR that will give you an indication, based on your results by area, as to how many times meth was smoked in your home.
NB: The Meth Calculator is a tool designed by ESR to help interpret the methamphetamine readings. Meth Xpert makes no warranty nor assumes any legal liability for the accuracy or completeness of the results of this calculator. It is intended as a guide only and is derived from the best available information at the time by ESR.