The Comptroller and Auditor General publishes a report on the central government funding of local government. The most recent report refers to 2017 and is available at the following link:
https://www.audit.gov.ie/en/Find-Report/Publications/2018/2017-Annual-Report-Chapter-04-Central-government-funding-of-local-authorities1.pdf.
The report outlines that in 2017 local authorities received a total of €2.66bn in transfers from central government.
The CSO publishes GDP and GNI statistics on its website and figures for 2017 are available at the following link:
https://cso.ie/en/releasesandpublications/ep/p-nie/nie2017/mainaggregates.
Figures from the CSO indicate that in 2017 Irish GDP was €293Bn and GNI was €233Bn. On that basis, central government funding of local government equated to 0.91% of GDP and 1.14% of GNI in 2017.
Details in relation the funding provided to local councils in other EU member states is not routinely collated in my Department but may be available from Eurostat at https://ec.europa.eu/eurostat.