The number of Catholics in the workplace has risen while there are fewer Protestants in work, the Equality Commission for Northern Ireland has revealed.
Firms with 11 or more employees must supply monitoring details
The commission's 13th annual monitoring report, published on Tuesday, was based on a survey of 481,117 people working in the public and private sectors.
Under fair employment legislation in Northern Ireland, all public and private sector companies with 11 or more employees must register with the Equality Commission.
The companies are required each year to submit details of the community background, employment status, occupation and sex of their workforce.
The report found that the number of Catholic employees increased by 1.7% in 2002, while the number of Protestants fell by 0.6%.
Protestants accounted for almost two-thirds of those approaching retirement, the report found.
Catholics made up 51% of those aged between 16 and 35.
The commission's survey also found that more than 50% of the workforce was female.
It said this figure was disproportionately high because of the number of women working part-time.
Eileen Lavery of the Equality Commission told BBC Radio Ulster that some of the changes were due to a rise in public service sector jobs.
"I think there are a number of factors behind this," she said.
"Firstly, the economy has been doing quite well, and in particular we have seen the services sector grow again.
She added that public sector employment had also increased.
"Where there is an increase in employment, there is opportunity for change and that opportunity has resulted in a small increase in Catholic participation," she said.
The Equality Commission was established under the terms of the Good Friday Agreement to oversee equal opportunities in areas including employment.
It was included in the Agreement to address nationalist and republican demands that the equality agenda in Northern Ireland should be examined.
The body replaced the Commission for Racial Equality for Northern Ireland, the Equal Opportunities Commission, Fair Employment Commission and the Northern Ireland Disability Council.
The commission is also responsible for ensuring that all public authorities in Northern Ireland give due regard to promoting equality of opportunity across a range of areas.
These include religion, political opinion, gender, race, age, marital status, sexual orientation, disability and those with and without dependants.