Migration movements include not only entries of persons of foreign nationality, on which public attention tends to be focused, but also include movements of nationals and of emigrants. Net migration summarises the overall effect of these movements. Migration currently represents, in almost all OECD countries, the main source of increases in population.
Net migration is defined as the total number of immigrant nationals and foreigners minus the total of emigrant foreigners and nationals. Arrivals and departures for purposes such as tourism and business travel are not included in the statistics.
The net migration rate is expressed per 1 000 inhabitants. The three-year averages referred to concern the years 2006 to 2008 (end of period); and 1995 to 1997 (beginning of period).
The main sources of information on migration vary across countries. This may pose problems for the comparability of available data on inflows and outflows of migrants. However, since the comparability problems generally relate to the extent to which short-term movements are covered, taking the difference between arrivals and departures tends to eliminate the movements that are the main source of non-comparability.
Despite this feature, net migration data should be interpreted with care, because unauthorised movements are not taken into account in the inflows and these unauthorised movements are significant in some OECD countries. In addition, the data on outflows are of uneven quality, with departures being only partially recorded in many countries or having to be estimated in others.
The net migration rate is used to describe the contribution of international migration to population increase, the other component being natural increase, defined as the difference between the number of births and the number of deaths in a given year.
Estonia, Poland, the Netherlands, Japan and Turkey are the only countries among those shown here that recorded negative or zero net migration in the three years to 2008. Ireland, Iceland, Luxembourg and Spain top the league showing net migration rates above 10 per thousand in recent years. The former emigration countries (Ireland, Italy, Portugal and Spain) figure prominently among those countries experiencing high net migration, a trend which is likely to continue in the future.
In most countries, net migration rates are higher than the levels recorded in the mid 1990s, with the increase being especially large in several Nordic countries, in countries in southern and continental Europe as well as in Australia. With the retirement of baby-boomers in the near future and the entry of smaller youth cohorts in the labour market, labour supply needs may well require a further rise in net migration in the future.
There are nonetheless a number of countries where net migration rates are currently lower than was the case five to ten years ago. These include Israel, New Zealand, the Russian Federation, Greece, Germany, Turkey and the Netherlands.