How many total grails will we get this year?

I think we will get 9 more until the end of year.4 from E Pluribus Unum, Camelot and Babylonia, and 5 from events.
If you search for the Holy Grail on the Grand Order wiki, it lists all the sources where you can get one, so it's pretty easy to check when the next ones will (probably) be available.