You get the economy point when the trade route returns to zero.
Trade is utterly worthless in this game guys, don't bother with it.
Option 1: Including the turn it takes to set up, it's going to take 9 turns to get back your 2 econ pt investment and 13 turns to make 1 econ point profit. You then begin getting one "free" econ point every four turns. Diagram (when you get 1 pt bonus in bold)
(0/3), (1/3), (2/3), (3/3),
(0/3), (1/3), (2/3), (3/3),
(0/3), (1/3), (2/3), (3/3),
(0/3), (1/3), (2/3), (3/3),
(0/3)
Option 2: It's still not that great even if one gets the econ point on the 3rd turn, taking 8 turns to break even and 12 turns to make a profit with "free" pt every four turns after that.
(0/3), (1/3), (2/3),
(3/3),(0/3), (1/3), (2/3),
(3/3),(0/3), (1/3), (2/3),
(3/3), (0/3), (1/3), (2/3),
(3/3)
Option 3: I really hope that I am misunderstanding the trade formula and it really works this way so that break even is 7 turns and profit is 10 and "free" pt every three turns after that.
(0/3)=initial investment turn, (1/3), (2/3),
(3/3), (1/3), (2/3),
(3/3), (1/3), (2/3),
(3/3), (1/3), (2/3),
(3/3)
Option 4: I could even live with this system, break even 8 turns, profit 11, but at least you get a "free" pt every three turns after that.
(0/3)=initial investment turn, (1/3), (2/3), (3/3),
(1/3), (2/3), (3/3),
(1/3), (2/3), (3/3),
(1/3), (2/3), (3/3),
(1/3)
So please, end the confusion (at least on my part), which system are you using? Or have I really severly screwed up in my calculations and your system is much more trader friendly than I protrayed?