Autonomous vehicle (AV) technology is considered to be the future of transportation and has gained much focus from academia, vehicle industries, transportation agencies, and the general public. To contribute to the existing literature, this study used three surveys carried out by the Puget Sound Regional Travel Study in 2015, 2017, and 2019 to identify the segments of the population based on AV adoption interest, the characteristics of such population segments, and the dynamics of AV adoption interest over time. Using $k$ -means clustering, three distinct levels of AV adopters in the increasing order of adoption interest were found: (1) skeptics, (2) indifferents, and (3) enthusiasts. Multinomial logit models of the clusters identified sociodemographic, household, residential, and travel-related attributes as significant predictors of the level of AV adopters. The AV adoption interest was found to increase gradually over time despite the increase of public AV concerns. Ways to increase AV adoption interest were discussed based on the study results.