These data are provided as supporting information for the manuscript "Empirically estimated electron lifetimes in the Earth's radiation belts: 1. Observations" by Claudepierre et al. These data include electron flux measurements in the Earth's radiation belt obtained with the MagEIS instrument on the NASA Van Allen Probe B satellite, along with the empirical decay timescale estimates described in the manuscript. The contents of the data files are described in greater detail in the corresponding "readme" files.