The presence of plasma waves upstream from the Martian bow shock, with frequencies near the local proton cyclotron frequency in the spacecraft frame, constitutes, in principle, an indirect signature for the existence of planetary protons from the ionization of Martian exospheric hydrogen. In this study, we determine the "proton cyclotron wave” (PCW) occurrence rate between October 2014 and February 2020, based on Magnetometer and Solar Wind Ion Analyzer measurements from the Mars Atmosphere and Volatile EvolutioN mission. We characterize its dependence on several wave and solar wind (SW) properties, and solar longitude ranges. We confirm a previously reported long‐term trend with more PCWs near perihelion, likely associated with changes in exospheric hydrogen density. Furthermore, we report for the first time a decrease in median PCW amplitude for each consecutive Martian perihelion. Such variability cannot be attributed to differences in the distribution of SW conditions. This trend could be associated with changes in solar inputs, foreshock effects, and asymmetries due to the SW convective electric field influencing newborn protons. In addition, we observe PCWs more frequently for low to intermediate interplanetary magnetic field (IMF) cone angles, slower SW speeds, and higher SW proton densities. The IMF cone angle preference likely results from the trade‐off between associated linear wave growth rates, wave saturation energies, and pick‐up proton densities. Moreover, the dependencies on SW speed and density indicate the importance of the characteristic SW transit timescale and the charge exchange process coupling SW protons with the hydrogen exosphere. Key Points We confirm an annual periodicity of proton cyclotron wave occurrence rate upstream from the Martian bow shock between October 2014 and February 2020 We report a decrease in median wave amplitude for each consecutive Martian perihelion based on available sampling of the Martian upstream region PCWs occur more frequently near perihelion for low to intermediate interplanetary magnetic field cone angles, slower solar wind speeds and higher solar wind densities