Some 18 percent of hospital CEO positions across the country turned over last year, according to new data released by the American College of Healthcare Executives, which is holding its annual Congress on Healthcare Leadership this week in Chicago.

The rate matched 2014’s numbers and fell just two percentage points shy of the record 20 percent turnover rate recorded by the ACHE for 2013.

“Our data show a continuation of the elevated CEO turnover rates we have seen over the past several years,” said ACHE President and CEO Deborah Bowen in a statement.

Bowen cited hospital and health system consolidation, new care-delivery models, executive retirements and the movement of individual hospital CEOs within multi-hospital systems as “contributing factors” to the continued high vacancy rate in the hospital C-suite.

Bowen failed to mention the elephant in the room by name: the Patient Protection and Affordable Care Act.

From 2011 through 2015—the first five years after passage of the ACA in 2010—the average annual hospital CEO turnover rate was 17.8 percent. From 2006 through 2010, it was 15.6 percent, strongly suggesting that healthcare reform is having an impact on the tenures of hospital CEOs. For example, the law established financial penalties for hospitals with poor patient safety records and high rates of patient readmissions.

In Minnesota, the hospital CEO turnover rate was 16 percent in 2015, or two percentage points lower than the national average, placing it 33rd among states, tied with Kentucky and South Dakota. Although the rate held steady nationally between 2014 and 2015, it jumped in Minnesota from 11 percent in 2014 to 16 percent last year.