We continue with Vatican II directives on the theme of baptism: how to receive formally (ie, through the clergy) those who have already been baptized:
In place of the rite called the “Order of supplying what was omitted in the baptism of an infant,” a new rite is to be drawn up. This should manifest more fittingly and clearly that the infant, baptized by the short rite, has already been received into the Church.
And a new rite is to be drawn up for converts who have already been validly baptized; it should indicate that they are now admitted to communion with the Church.
And this latter provision accounts for half to three-fourths of RCIA work in my experience.
Any comments?
Catholic Sensibility 
I’d say your percentage is high compared to my experience, where I have worked in parishes where uncatechized/poorly catechized Catholics are placed into RCIA: they usually form a small majority.
Good point, Fr Fox. I’ve never included uncatechized Catholics when I’ve been in charge, and many RCIA directors steer them to a different track or setting. Our parish “catches” people up with confirmation classes annually.