Nigerian citizens were the largest single group among those who received Irish citizenship in 2013, according to figures by Eurostat.

Nigerian citizens represented a quarter, or 23.9 per cent, of all Irish citizenships granted that year.

Indian citizens were the second largest group among those who received Irish citizenship in 2013, at 12.4 per cent, followed by citizens of the Philippines, at 10.2 per cent.

Proportionately, the State granted the highest rate of citizenship per 1,000 of the resident population in 2013 in the EU.

When compared with the total population of each EU member state, the highest rates of citizenship granted were recorded in the State (5.3 citizenships granted per 1,000 of the resident population), Sweden (5.2), Spain (4.8) and Luxembourg (4.7).

On average, 1.9 citizenships were granted per 1,000 inhabitants in the EU.

The Republic was the third main EU member state granting citizenship to Indian and Pakistani citizens in 2013, behind Italy and the UK in both cases.

Seven per cent of those acquiring Irish citizenship in 2013 were citizens of another EU member state, and 93 per cent were from outside the EU.

EU citizenship

At EU level as a whole, Moroccans (8.8 per cent per 1,000 inhabitants in the EU), Indians (4.9 per cent) and Turks (4.7 per cent) were the largest groups gaining citizenship of an EU country.

Romanians and Poles were the two largest groups of EU citizens acquiring citizenship of another EU member state in 2013.

In 2013, the highest naturalisation rates were registered in Sweden (7.6 citizenships granted per 100 resident foreigners), Hungary (6.5) and Portugal (5.9), and the lowest in Slovakia (0.3), the Czech Republic and Denmark (both 0.5).

The naturalisation rate is the ratio of the number of persons who acquired the citizenship of a country during a year over the stock of foreign residents in the same country at the beginning of the year.

Of the five EU member states that granted the most citizenships in 2013, the naturalisation rate was above the EU average in Spain (4.5) and the UK (4.2), while it was below the EU average in France (2.4), Italy (2.3) and Germany (1.5).