The curation of seismic data sets is the cornerstone of seismological research and the starting point of machine-learning applications in seismology. We present a 21-year-long AI-ready data set of diverse seismic event parameters, instrumentation metadata, and waveforms, as curated by the Pacific Northwest Seismic Network and ourselves. We describe the earthquake catalog and the temporal evolution of the data attributes (e.g., event magnitude type, channel type, waveform polarity, and signal-to-noise ratio, phase picks) as the network earthquake monitoring system evolved through time. We propose this AI-ready data set as a new open-source benchmark data set.