The concept of open data and software for electric propulsion is discussed and exemplified by an open database that contains over 40 years of thermionic orificed hollow cathode experimental data. Because scaling laws for electric propulsion devices must be verified over a wide range of operating conditions, access to data is critical. Examples of statistical analysis that can be performed with the dataset and resulting physical insights are presented. The empirical analysis conducted suggests that the ratio of total to magnetic pressure inside hollow cathodes depends on at most two other non-dimensional parameters and that the value of 3.7 Torr-cm for the total pressure-insert diameter product is likely a sufficient condition for nominal cathode operation. Solutions to increase the sharing of data and software in the electric propulsion community are suggested.