Familiarity with FAIR Data Principles by Subject Area, 2018 & 2025. Researchers were asked: "How familiar are you with the FAIR data principles (i.e. Findable, Accessible, Interoperable and Reusable)?" Response options included: never heard of FAIR before, previously heard of FAIR but not familiar with the principles, and familiar with FAIR. Yearly sample sizes: 2018 (n = 1,239), 2025 (n = 3,932).