A long-standing concern that the number of registered voters seems high when compared to the 6.2 million population over the age of 18 years was mentioned to the Venice Commission during its expert visit.44 As described in the OSCE/ODIHR election observation mission report on the 2013 parliamentary elections, the size of the population is calculated based on the population that is present on the territory of the country or has left the country for a period not exceeding one year. In contrast, the number of voters encompasses all Bulgarian citizens with voting rights, including citizens residing abroad. This partly explains the difference between the numbers of population and registered voters.