If you are looking for migration statistics to/from Ireland, then the 2 organizations shown below are a good place to start.

The Central Statistics Office has a wealth of information about who is coming to the country and who is leaving.

Also the European Migration Network Ireland is another good source of population statistical information. You can find migration charts at this link which show emigration, immigration and net migration figures from 2000 - 2014.
"The aim of the European Migration Network is to provide up-to-date, objective, reliable and comparable information on migration and asylum at Member State and EU-level with a view to supporting policymaking and informing the general public" (source emn.ie)