Canada's missing drugs: Here's how we crunched the numbers

Every time controlled drugs go missing from a pharmacy, hospital, transport company or another facility, details about the loss must be reported to Health Canada within 10 days.

Controlled drugs are those Health Canada has identified as having a higher-than-average potential for abuse or addiction.

CBC News obtained all loss reports across Canada between Jan. 1, 2012 and Sept. 30, 2017 in an access-to-information request. Over that time period, there were 142,420 individual reports filed with Health Canada.

• Download the raw data and see full methodology here

The quantities of drugs lost were measured in 18 different units, not all of which were easily convertible. These varied from tablets to millilitres to, in the case of cannabis, plants and seeds.

CBC News limited its analysis to losses measured in capsules, tablets, patches, packages or suppositories. Each of these were counted as one unit reported lost. Together, they accounted for 93 per cent of the loss reports in the data.

Losses measured in metric units (such as milligrams) or imperial (such as ounces) were not included in CBC's overall analysis.

CBC's analysis also does not include drugs that were not reported missing to Health Canada, such as unused amounts from legitimate prescriptions sold for profit on the street and unused narcotics disposed of by hospitals and pharmacies.