You don not have to p**** all 109MB. Just look for spieler_t records. The entries with sint64 are the player statistics. Those are first per year and then per month the following categories:
COST_CONSTRUCTION=0,// Construction
COST_VEHICLE_RUN, // Vehicle running costs
COST_NEW_VEHICLE, // New vehicles
COST_INCOME, // Income
COST_MAINTENANCE, // Upkeep
COST_****ETS, // value of all vehicles and buildings
COST_CASH, // Cash
COST_NETWEALTH, // Total Cash + ****ets
COST_PROFIT, // COST_POWERLINES+COST_INCOME-(COST_CONSTRUCTION+COST_VEHICLE_RUN+COST_NEW_VEHICLE+COST_MAINTENANCE)
COST_OPERATING_PROFIT, // COST_POWERLINES+COST_INCOME-(COST_VEHICLE_RUN+COST_MAINTENANCE)
COST_MARGIN, // COST_OPERATING_PROFIT/(COST_VEHICLE_RUN+COST_MAINTENANCE)
COST_ALL_TRANSPORTED, // all transported goods
COST_POWERLINES, // revenue from the power grid
COST_TRANSPORTED_PAS, // number of p****engers that actually reached destination
COST_TRANSPORTED_MAIL,
COST_TRANSPORTED_GOOD,
COST_ALL_CONVOIS, // number of convois
COST_SCENARIO_COMPLETED,// scenario success (only useful if there is one ... )
Since the code is object oriented, documenting the savegame is not easy, as every version could change its entry complete (although usually only one or two thing in an entry are changed; but 101 is very different from 100, as nearly everything is changed.) A similar tactic works for convois and cities too.
Since I would not use this funtion, I have no incentive to do it. But some other players requested it, maybe you can motivate somebody. But there will be h****les, like what format and how to create a file.