The stability in the proportion of individuals of French origin was due to their high fertility rate; the decrease in the relative proportion of persons of British origin stemmed from the significant role that international immigration played in demographic growth dur- ing the years before and after the First World War. [...] The length of exposure to the risk of linguistic mobility varies from one person to the next and depends on age as well as the situation in which the person has spent the different stages of his or her life cycle. [...] Of course, the Francophone population can be defined in several other ways depending on the requirements of the study or the needs of the users. [...] If the proportion is higher than the national average in a region, the proportion of this region’s Anglophones in the country’s entire Anglophone popu- lation will exceed the proportion of the regional population in the national popula- tion (Table 1.2). [...] The proportion of Francophones in all the divisions in the south of the province is below 10%.