The number moving out fell by 10.3% to 22,800 people between July 2013 and June 2014, the NI Statistics and Research Agency (Nisra) revealed.
In the same period, 24,400 people moved to Northern Ireland, meaning an increase in net immigration of 1,600.
During Northern Ireland's economic boom years, annual net immigration peaked at almost 11,000.
Nisra said the number of people leaving Northern Ireland was at its lowest level in five years.
The overall Northern Ireland population was estimated to be 1.84 million in June 2014, an increase of 10,800 on the previous year.
That growth of 0.6% was the highest in the last four years.
That was made up of net immigration plus natural growth of 9,800 (24,200 births compared to 14,300 deaths).
Meanwhile, the number of military personnel in Northern Ireland fell by 600.
The statistics also confirmed a continued ageing population.
There are an estimated 285,000 people aged 65 and over.
The proportionate population increase of that age group, 2.4%, was more than nine times that of the population under 65.
More people have moved to Northern Ireland than left for the first time in four years, official estimates suggest.