Get the latest year for cost uplift latest_cost_year() is hard coded in cost_uplift(). 2223 is not changed automatically with time passes. It is changed only when we get a new instruction from somewhere about cost uplift. Do not change unless specific instructions. Changing this means that we need to change cost_uplift().
See also
Other initialisation:
get_dd_period(),
latest_update(),
previous_update(),
years_to_run()