If there have been problems with the Medicare prescription drug benefit, beneficiaries are not squawking about it, suggests a new report from the Centers for Medicare & Medicaid Services.

CMS received about 2.3 complaints related to the benefit for every 1,000 beneficiaries enrolled in Medicare drug plans, according to data released this week. Most of the complaints were related to enrollment or disenrollment in drug plans.

Less than one complaint per 1,000 beneficiaries was related to problems obtaining needed drugs or plan customer service. The data will be used to find plans’ problems and to address problems in customer service, CMS said.