I'm not a modular i did integrated.
180 737's yay, but 75 are for replacement so that downs the number to 100 NEW 737's till 2018, not 180 as you say.
100 till 2018 (3 yrs) will be more or less 30 new 737 per year (300 pilots) without taking into account the ones arriving for replacement.
300 pilots plus the one who leave for the sandpit you get more or less 600 pilots each year, but from this number substract the grads from OAA & CTC and you get 400 pilots hired that don't come from OAA & CTC.