Measurements were performed in a propylene carbonate solution at room temperature (22 o C). STM tips were coated with Apiezo wax to minimize the exposed area to polar solvents and to reduce the non-Faradaic current. Single-molecule conductance data were acquired at a sampling rate of 40 kHz. During experiments, the STM tip is controlled by a piezoelectric micro-positioner to repeatedly form and break molecular junctions, and the current was recorded and analyzed during this process. A variable-gain low noise current amplifier (DLPCA-200 from Artisan Technology Group) was used to accurately convert current to voltage for data processing. Data were obtained across molecular ensembles of at least 5,000 molecules and collected and analyzed without data selection. 2D conductance histograms were determined by aligning single-molecule conductance traces relative to the junction formation point (denoted as 0 nm displacement). 2D conductance histograms were fit with linear regression trend lines to better visualize and demonstrate conductance evolutions during the pulling process of STM-BJ experiments. To perform the linear regression fitting, the 2D conductance histograms were first transformed into 50 distinct 1D conductance histograms at equally spaced intervals of junction displacement, such that each of the 1D conductance histograms correspond to the conductance distribution at a particular junction displacement.