Key Finding: This chart presents, per year, the percentage of claims that were found unpatentable or cancelled out of those challenged by the petitioner in IPR proceedings that reached final written decisions or were denied institution on substantive grounds. The data show a drop in unpatentability findings over the years, with a leveling off in 2017-2018. It is unclear if the trend over time stems from adjustments by the PTAB, the quality of patents challenged by petitioners, the quality of petitions/defenses, or some combination thereof. The listed periods are for final written decisions. The analyzed decisions not to institute are from one year earlier.