The projections calculated based on the 1991 Population Census, were established under the assumption of a constant annual flow of entries from abroad equal to 35 thousand people during the entire projection period, in agreement with the figures that were being registered. However, as of 1998, the comparison of the projected flows with those observed reflects a deficit in the prior ones that is especially significant in the year 2000, due to the extraordinary increase in the arrival of foreigners experienced.

Beginning with the most simple component in the case of Spain, migrations abroad have been supposed as null, as with the projection object of this revision.

Referring to immigration, among the different sources of information, Change of Residence Statistic (CRS), Populations Censuses, Migrations Survey… the first has been considered the most adequate, both from a practical and theoretical viewpoint, given the flows covered for the following of the same.

The changes in the management of the Municipal Registers, brought about by modifications to the 1996 regulations, have caused the CRS to adjust to new, not yet consolidated, information sources

Consequently, immigration in the CRS, is that in which citizens declare their origin as from abroad upon inscribing in the Municipal Register, these must be completed with the discharges by omission registered in the Continuous Register, which are those that correspond to individuals who at the time of inscribing themselves in a certain municipality manifested their origin as from abroad.

It is necessary to differentiate the arrivals by nationality: Spanish or foreign.

Referring to the population of Spanish nationality, the CRS flows available for the 1991-1999 period have been considered more adequate.

Referring to foreign population, the CRS figures for the 1991-1997 period have been considered more adequate. For 1998, 1999 and 2000, the Registers figures are taken into account.

The fact of not being able to calculate risks of immigration (independent of nationality) and the spectacular changes registered in the last two years in the arrival of immigrants to Spain, does not permit the establishment of consistent hypothesis. It would be more appropriate to talk about scenarios, in the sense of determining what would be the growth and the age structure of the population. Due to this, when setting a total volume of arrivals in the present revision, three alternatives have been established, which are covered in this file.

The flows used in the revision correspond to hypothesis 1. They have been distributed by Autonomous Communities and by Provinces according to the average of the observed distributions for 1998 and 1999 in the CRS.

Distribution by sex and age in each one of the geographical scopes considered has been established by applying the average of the observed distributions for 1998 and 1999 in the CRS from the Continuous Register.

Domestic migrations are those that occur as a consequence of the changes of residence municipality within Spain. Among them, it is neccesary to distinguish the changes of Autonomous Community of residence and the changes of Province of residence, thus facilitating, respectively, the interautonomic and interprovincial migrations.

At the time of carrying out the present revision the observed CRS figures are used for the 1991-1999 period. Those corresponding to 1991-1994 were already incorporated at the time in the projections, due to which the exits and arrivals observed between 1995 and 1999, distributed by sex and age according to national total of interautonomic migrations, are added.

For the 2000-2005 period, constant and equal global interautonomic mobility rates have been applied, for each sex, to the semi-sum for 1997 and 1998. The distribution by simple ages is calculated applying the average of the 1997 and 1998 distributions, thus the development is more recent.

For the update of the Provincial figures after 1994, those observed between 1995 and 1999 have been incorporated. As of this last year, a balance has been estimated, for each Province, as an average of the balances observed in 1997 and 1998, which is distributed by five year age groups according to the same distribution as the interautonomic migrations. The resulting flows by Provinces are adjusted to those corresponding to Autonomous Communities by means of a proportional distribution.