Not all hospitals are created equal.

That’s why the nonprofit organization, The LeapFrog Group, which advocates for transparency in US healthcare, assigns safety grades to thousands of hospitals nationwide twice a year. These rankings are a valuable tool for patients choosing where they’d like to receive their care and for healthcare professionals interested in improving their job performance.

To grade 2,600 general acute-care hospitals across the country, Leapfrog’s system relied on data from the Centers for Medicare & Medicaid Services (CMS), the Leapfrog Hospital Survey (for which hospitals voluntarily disclose their safety data), and other supplemental sources. The final grade, which ranges between A and F, reflects 28 measurements of hospital safety — including rates of infections and patient falls, quality of communication between patients and staff, practices to prevent errors, and more. (Learn more about the Leapfrog methodology here.)

This year’s spring rankings came out last week and included several interesting revelations. Namely, patients at D and F hospitals are up to 92% more likely to die from an avoidable error than patients at A hospitals. (For C hospitals, that number was 88%, and for B, it was 35%.) For context, Leapfrog researchers found that if all US hospitals were at the A level, about 50,000 lives would be saved annually. This year, some 160,000 people died from medical errors (for which there is publicly available data). While that number is sobering, it’s a drastic improvement from 2016’s estimated 205,000 lives lost from avoidable hospital mistakes.

“The good news is that tens of thousands of lives have been saved because of progress on patient safety. The bad news is that there’s still a lot of needless death and harm in American hospitals,” said Leah Binder, president, and CEO of the Leapfrog Group, in a statement. “Hospitals don’t all have the same track record, so it matters which hospital people choose, which is the purpose of our Hospital Safety Grade.”

Other findings include the following:

• The grade-percentage breakdown: 32% earned an A, 26% a B, 36% a C, 6% a D, and slightly less than 1% an F.

• Oregon, Virginia, Maine, Massachusetts, and Utah have the highest percentage of A-ranked hospitals, with 58%, 53%, 50%, 48%, and 48%, respectively.

• Wyoming, Alaska, Washington, D.C., Delaware, and North Dakota have no A hospitals.

Search for your hospital’s grade and see where your state ranks in overall hospital safety here.