FACTBOX-Key facts about Ireland

(Reuters) - Voters in Ireland will decide in a referendum on June 12 whether to back the European Union's Lisbon treaty, which is to replace the defunct EU constitution.

Here are some key facts about Ireland.

AREA - 70,284 square km (27,140 square miles). The Republic of Ireland is made up of 26 of the 32 counties of the island of Ireland. The six counties of Northern Ireland are part of the United Kingdom.

POPULATION - 4.3 million

RELIGION - Catholic 87 percent, Anglican 3 percent.

LANGUAGE - The official languages are Irish and English but most of the population uses English. Irish is a compulsory subject in all schools that receive state funding.

CAPITAL - Dublin

ECONOMY - Ireland has gone from one of western Europe's poorest nations to one of its richest since the Celtic Tiger boom of the 1990s. Having grown at 2 to 3 times the average EU rate in recent years, the economy has cooled sharply over the last year as an end to a decade-long property boom, when house prices quadrupled, put the brakes on growth. Gross domestic product is set to grow 1.6 percent this year, down from 5.3 percent in 2007, according to the latest Reuters survey.

-- House prices fell for the 14th month in a row in April, dropping 9.2 percent year-on-year, and mortgage growth slowed to its lowest annual level in almost 16 years.