From non-Irish. The birthrate for Ireland has remained stagnant from 1996-2016, remaining at less than 2 children per Irish woman, or below replacement levels, for decades.
According to the census statistics office of Ireland, actual Irish people are 2nd to last on the growth charts measuring years 2011-2016. The #1 category for growth from 2011-2016, was something the Irish government terms 'Other (Incl Mixed Background)', which is a way of obscuring who or what these people actually are.
The 2nd highest growth category was Asians, which dwarfed the Irish growth rate.
Ethnicity - CSO - Central Statistics Office
Interestingly, despite obvious signs of demographics change in Ireland, it's government has now used the same figure of 82.2 to represent the white Irish share of the population for many years now, further evidence of obfuscation when coupled with the vague description of who the 'Other (Incl Mixed Background)' are.
Well, I can tell you who Ireland's leadership anticipates will comprise the 1 million figure from population growth in the Project 2040 Plan, even though it isn't stated in the official literature.
Tánaiste (Deputy Prime Minister) Simon Coveney, when asked about the UN's Global Migration Pact, said:
"We estimate over the next 20 years that the population of Ireland will certainly grow by an extra million people. Linked to that estimate is that half of that number won't have been born in Ireland. I think that will be a really good thing for Irish society, not but we do need to manage or carefully, so we don't allow the politics of migration to play a big part in Irish politics, because I think it pulls us in a dangerous direction."
Note: I'm relegated to using an audio recording of Coveney's words as a source, because NO IRISH MEDIA COMPANY BOTHERED TO PUBLISH THEM, AFTER HIS WORDS SURFACED. Perhaps this is the result of Leo Varadkhar paying the Irish press to only speak positively in regards to P2040? We'll never know, because transparency is clearly not at the heart of this agenda.
Coveney further stated that the 1 million figure of growth in the next 20 years would consist of foreigners (500k), their children (who knows how many), and the rest being Irish.
Now I'll wait for all those who scoffed at the OP to admit they were wrong. Go on... anybody man enough to admit error?