In the early years of European migration to Nueva Navarra, the Basques became a significant proportion of the population. The Basque immigrants reached 6% of total migrants in the first 15 years of colonization, the same percentage as those from the Castile or Extremadura, most populated regions. More specific data shows ratios between 8% and 16% of Basques in the nuclei urban settlements of those first decades, indicating a trend which would persist in the future: the Basque-Navarre preference for urban settlement (Boyde-Bowman, 1964).