Persons aged 75 and over accounted for two-thirds (66.9%) of all deaths and 79.3% of COVID-19 related deaths registered this calendar year up to 15th May.
Nisra publishes weekly statistics which total all deaths where coronavirus has been recorded on the death certificate.
The latest Nisra report says that by last Friday - out of 664 Covid-19 related deaths recorded in total - 303, (45.6%), occurred in care homes; 322 (48.5%) occurred in hospital and six (0.9%) occurred in hospices.
The number of people who have died after testing positive for coronavirus in Northern Ireland has risen to 504 after three more deaths were reported by the Department of Health.
Most (32) occurred in care homes, which represents a drop from 38 the previous week and 72 in the week before.
Thirty-three deaths happened at residential addresses or another location.
They may or may not have previously tested positive for the virus.
Dr Ronan Glynn, Deputy Chief Medical Officer, Department of Health, said: "Research conducted on behalf of the Department of Health shows that 86% of people rate their knowledge on how to prevent the spread of COVID-19 as high".
This measure captures all deaths caused by the coronavirus: the infections that were confirmed and feature in the daily figures; as well as the suspected cases that were mentioned on the death certificate.
The 115 new cases that were confirmed brings the total number of cases in the Republic to 24,506.
Health Minister Robin Swann said he hopes the monthly report will "ensure that there is the maximum possible transparency" around coronavirus. Prevalence of the virus remains low in the community.
"The valuable and detailed analysis contained within the monthly bulletin will help us to develop our plans for the vital recovery period as we start to re-engage our health and social care services".