Legend - Type List - Updates
TradeableItems:
-1 = TRADE_ITEM_NONE
0 = TRADE_GOLD
1 = TRADE_MAPS
2 = TRADE_OPEN_BORDERS
3 = TRADE_DEFENSIVE_PACT
4 = TRADE_PERMANENT_ALLIANCE
5 = TRADE_PEACE_TREATY
6 = NUM_BASIC_ITEMS
7 = TRADE_YIELD
8 = TRADE_CITIES
9 = TRADE_PEACE
10 = TRADE_WAR
11 = TRADE_EMBARGO
12 = NUM_TRADEABLE_HEADINGS
12 = NUM_TRADEABLE_ITEMS