Did some analysis of the 227 players currently on the four Irish provincial squads, plus the full academies, looking at where the players were produced.
The four squads are roughly equal in size, Leinster are the largest at 61, then Munster at 58, Ulster at 56 followed by Connacht at only 52.
School Location
101 players total (44%) are produced by schools within the Leinster system, 43 players (19%) within the Munster system, 32 players (14%) in the Ulster system, and just 13 players (6%) from a school in the Connacht system. 38 players (17%) were educated overseas.
School Classification
52% of all players (117 players) are produced from a private secondary school in Ireland, 72 (32%) from a public school, and the residual 38 (17%) from a foreign school. I haven't broken down the foreign schools by public v private.
Largest Producer
The most telling stat from the analysis is the following: 20% of all Irish players (44 players) come from two schools, Blackrock College & St Michael's College. Blackrock account for 24 players and Michael's 20. Next largest school seems to be Pres in Cork, with 12 players (5%).
Squad by Squad Analysis
The Leinster squad has the most indigenously produced players (54 players - 88%), and the highest percentage of privately educated players (44 players - 72%).
Munster most heavily rely on their own schools (41 players - 71%) and have the second highest percentage of privately educated players (34 players - 59%).
Ulster produce 54% of their own players (30 players), but the remaining quotient of Ulster players are produced evenly from foreign schools and Leinster schools, both 13 players (23%).
Connacht have a reliance on the Leinster school system, which accounts for 48% of their squad (25 players), with the next highest percentage coming from abroad (27%),