It is not possible to provide the information requested by the Deputy as this is an individual decision by an Irish citizen taken following naturalisation.
Under the Irish Nationality and Citizenship Act 1935, if a citizen of the State, aged 21 years or over, became a citizen of another country they ceased to be a citizen of the State. The 1935 Act was repealed by the Irish Nationality and Citizenship Act 1956 and new provisions were enacted, which conditionally permit Irish citizens to also hold citizenship of other countries. Retention of their former citizenship by a person following naturalisation is not prohibited under Irish law. However, the Act provides that the Minister may revoke a certificate of naturalisation if he is satisfied that the person to whom it is granted has by any voluntary act, other than marriage or entry into a civil partnership, acquired another citizenship. I have no plans at present to amend legislation to prohibit the holding of more than one passport by an Irish citizen.