Figures released by the Health Insurance Authority show that there were 2.1 million people insured with in-patient health cover at the end of June 2012.
It represents a reduction of 16,000 people over the second quarter of the year, and 61,000 over the past year.
The HIA says the number of people insured has been in decline since it peaked at almost 2.3m people at the end of 2008.
In addition to those insured with in-patient plans, 103,000 people have cover solely for outpatient benefits or health insurance cash plans.
