Data on the epidemiology of aortic stenosis (AS) are primarily derived from single center experiences and administrative claims data that do not delineate by degree of disease severity. An observational cohort study of adults with echocardiographic AS was conducted January 1st, 2013-December 31st, 2019 at an integrated health system. The presence/grade of AS was based on physician interpretation of echocardiograms. A total of 66,992 echocardiogram reports for 37,228 individuals were identified. The mean ± standard deviation (SD) age was 77.5 ± 10.5, 50.5% (N = 18,816) were women, and 67.2% (N = 25,016) were non-Hispanic whites. The age-standardized AS prevalence increased from 589 (95% Confidence Interval [CI] 580-598) to 754 (95% CI 744-764) cases per 100,000 during the study period. The age-standardized AS prevalences were similar in magnitude among non-Hispanic whites (820, 95% CI 806-834), non-Hispanic blacks (728, 95% CI 687-769), and Hispanics (789, 95% CI 759-819) and substantially lower for Asian/Pacific Islanders (511, 95% CI 489-533). Finally, the distribution of AS by degree of severity remained relatively unchanged over time. The population prevalence of AS has grown considerably over a short timeframe although the distribution of AS severity has remained stable.