In seasonal grazing migrations, cattle are moved every year, and they are also led down to Senegal for sale. The droughts of the 1970s and early 1980s led to mass migrations to the towns. The population was 12% nomadic in 1988, compared to 83% in 1963. Some tribesmen of the Senegal River valley go to Dakar in Senegal for seasonal work or to engage in petty trade. A few thousand Mauritanians live in France. There were 6,000 Mauritanian refugees in Mali as of 1999.
Between June 1995 and 1997, 36,000 Malian refugees in Mauritania returned home. There were still 6,782 Malian refugees remaining in Mauritania in March 1997. In 2000 the net migration rate was 3.4 migrants per 1,000 population. That year the number of migrants in the country was 63,000. The government views the migration levels as satisfactory.