The naturalisation rate is the ratio between the number of persons who acquired the citizenship of a country during a calendar year and the stock of non-national residents in the same country at the beginning of the year. The term 'naturalisation rate', however, is doubly misleading: first of all because the numerator includes all modes of acquisitions and not just naturalisations, then because it should not be interpreted as a demographic rate since the denominator includes all non-nationals and not the relevant population, i.e. those non-nationals who are eligible for naturalisation.