The standard rate cut off point increased by €750 in Budget 2018 for all earners, e.g. from €33,800 to €34,550 for single individuals and from €42,800 to €43,550 for married one earner couples.
As published in Budget documentation, at the time of Budget 2018 it was estimated that the first year (i.e. 2018) cost of the increase would be €132 million, and that the full-year cost of the measure (applying from 2019 on) would be c. €152 million.
The Post-Budget 2018 Ready Reckoner published by the Revenue Commissioners shows (on page 3) the estimated number of taxpayer units paying tax at the standard and marginal rates in 2018: https://www.revenue.ie/en/corporate/documents/statistics/ready-reckoner.pdf. Estimates for the number of taxpayer units paying tax at the marginal rate in 2019 (and beyond) are not available.
Data contained in the Ready Reckoner are estimates for 2018, using actual data for the year 2015 (the latest year for which data are available) adjusted as necessary for income, self-employment and employment trends in the interim. They are provisional and may be revised.