From their FAQ: Why doesn't the site include data from before 2017? We do not feel that data collected retroactively would meet our rigorous research standards

From their FAQ: Why doesn't the site include data from before 2017? We do not feel that data collected retroactively would meet our rigorous research standards. We believe that data collected before we established a tracking system, methodology, and outreach is likely to be less comprehensive and therefore likely to underestimate the number of incidents before 2017. So it's a record number of journalists arrested since... 2017?! And finally, the definition of journalist: Who does the U.S. Press Freedom Tracker count as a journalist? The U.S. Press Freedom Tracker adopts a functional definition of who is a journalist. It doesn’t matter whether the individual has a press pass or went to journalism school, whether they work for The New York Times or work for themselves. What matters is whether the person was performing an act of journalism. The Tracker will count journalists whose rights to gather and disseminate information were violated in the course of their work or as a result of their work. In the case of border stops, the resistance of U.S. authorities to provide information makes it extremely difficult to identify whether a journalist has been stopped because of their work. So although it is possible that some journalists may be stopped for other reasons, we will report cases of all journalists who are stopped at the border and questioned for a certain amount of time. A journalist who attends a protest in order to protest publicly, rather than to document the protest, and is arrested or attacked in that capacity will not be counted on the site. While we recognize the importance and the rights of the private citizen who snaps a photo or video of an arrest, this site will only cover individuals who self-identify as journalists and have some track record of journalistic work. In summary: this is a meaningless article.