The number of couples getting married has fallen since the recession, while the average age of the bride and groom is on the rise.
There were more than 20,000 weddings registered in 2010, with almost seven out of 10 celebrated in a Catholic Church while nearly 6,000 - 29% of all ceremonies - were civil marriages.
But the rate was the lowest in the state since 1998, when it was also 4.5 per 1,000 of the population. The Central Statistics Office (CSO) said figures soared in the boom years to 5.2, but have been steadily dropping since 2008.
Elsewhere there were 3,113 divorces granted by the courts in 2010, down 7%.
The average age of grooms that year rose to 34.1 years, up from 26.2 years in 1977, while a bride's average age was 32 years, up from 24 in 1977. Just 4% of grooms and 7% of brides were under 25, while civil ceremonies were more common for couples over 40.
There were 18,175 first time marriages, while 2,226 involved at least one divorced person and both parties were divorced in 414 unions.
Just 427 of all marriages were in the Church of Ireland and the remaining 2% was made up of Presbyterian, Methodist, Jewish and other ceremonies.
Meanwhile the summer month of July remained the most popular for marrying, when 13% occurred. Saturday July 31 was the most popular date when 257 (1%) couples wed, closely followed by Friday September 10, when 255 (1%) marriages were celebrated.
January and Sundays continued to be the least popular month and day.