Figures from the Health Insurance Authority show that 66,000 people dropped their inpatient health insurance cover last year.
It says that 2.163m people had cover at the end of December, meaning that 47% of the population are covered.
The HIA says the average premium paid for each insured person last year was €926, an increase of 6% on the previous year.
The number of people insured has been in decline since the end of 2008.
VHI looses 278,000 customers in three years
The country's largest health insurer, VHI, has lost more than a 278,000 customers since December 2008.
It includes people who have given up private insurance and those who've transferred to other providers.
The figures were obtained from Irish Patients Association from VHI.
In the same period 134,000 left the private health insurance market.
It represents a 9% loss in VHI's share of the market from 65% to 56%.
Quinn Healthcare, which has 22% share of the market said its membership is broadly the same, while Aviva with 17% market share, said its numbers have gone up over the past three years.
Series of health insurance hikes from Thursday
A series of planned price increases by health insurers will come into effect on Thursday when VHI Healthcare introduces a range of price hikes to some of its most popular insurance plans.
Health insurance experts are advising consumers to contact their insurers or insurance brokers before the price increases are imposed to see if cheaper alternatives are available to their existing plans.
VHI, Quinn Healthcare and Aviva customers renewing their insurance in March are facing significant increases in premiums.
For example VHI's plan b and plan b with options, which cover a fifth of its customers will increase in price by 9 and 12.5 percent respectively from 1 March.
Taking price hikes imposed over the past year into account the cost of some health insurance plans will have increased by over 60% for consumers renewing with VHI, Quinn and Aviva after March.
Health insurance experts say in many cases, however, consumers may be overpaying for their coverage
They say in some instances people could save money either by switching to a different insurer or availing of corporate health insurance plans which offer an equivalent level of cover at a much lower price.
The health insurance authority's website hia.ie provides advice and price comparisons to assist those renewing their coverage or taking out health insurance for the first time.
443 patients on trolleys
Separately, there are 443 patients on trolleys in hospital emergency departments today, according to figures from the Irish Nurses' and Midwives Organisation.
The worst affected is Cork University Hospital where 57 patients are waiting.