The "Average Caribbean Wage" is provided in the almanac. It is located on the "Income Disparity" page, as the last item just above the graph, ... The Average Caribbean Wage tends to rise steadily throughout the game, ...
Caribbean, that is. It is linked to the Economic Difficulty slider in the game setup. It
probably always starts at the same amount; but in any case, it then increases on a
straight-line progression the steepness of which varies with the economic difficulty setting. It tops out at the 70 year amount or $50 which ever comes first; therefore, if you play for centuries, it ceases to be a factor.