Hospital Information: Outpatient Cost to Charge Ratio - History ST LUKES WARREN HOSPITAL Click here to download this table. Ratio Effective Date 008.07% 1/1/2018 008.15% 8/1/2016 008.43% 1/1/2016 008.01% 8/1/2015 008.41% 1/1/2015 008.17% 7/21/2014 008.60% 1/1/2014