CVS Health will close hundreds of drugstores over the next three years, as the retail giant adjusts to changing customer needs and converts to new store formats.

The company said Thursday that it will close about 300 stores a year for the next three years as it looks to reduce store count density in some locations.

The total of around 900 amounts to nearly a tenth of the roughly 10,000 retail locations CVS Health operates.

The company also sells insurance and runs prescription drug plans for big clients like insurers and employers.