GEN V: 19 before 4 months of the relase
GEN VI: 19 before 4 months of the relase
GEN VII; 25 before 4 months of the relase

Also,i think it's pretty much confirmed that we're getting more than kalos at least...

Starters (9)
Pikipek (12)
Yungoos (14)
Grubblin (17)
Rockruff (19)
Komala (21)
Cutiefly (23)
Bruxish (24)
Togedemaru (25)
Drampa (27)
Salandit (29)
Bewear (30)
Mimikyu (31)
Bounsweet (33)
Comfey (34)
Mudsdale (36)
Wimpod (38)
Legendaries (41)
Topu Keko & Friends (44)
Mystical (47)

So we pretty much know around... 47 new pokemon,and there's more coming in august.

Anyone who thinks that we're getting under 72 mons is stupid,sorry.
I think it's pretty obvious that we're getting over 72 anyway,if you want to live in denial and not accepte this good for (you)