text: DIP tests have four main outcomes: positive for opiates (which mainly indicates heroin use); 
  positive for cocaine use (which may indicate powder- or crack-cocaine use); positive for both; or 
  negative. Data are available from 2004 to 2013 as shown in Table 1, though the 2013 data 
  cover the period up to November 2013 only, so in this and subsequent tables we include an 
  additional column ‘2013 adjusted’, which simply multiplies up the existing 2013 figures by 1.09 
  (12 divided by 11) to account for the missing month’s data.7 