What percentage of baptisms performed in Novus Ordo churches by Novus Ordo priests are invalid?

I've heard stories of people being baptized in the names of the "God, Redeemer, and Sanctifier" or some other invalid form. How common is this?

I won't attempt to guess a percentage.  I DO know that my "first" Confirmation was invalid due to defect of form and matter.  The other five dozen or so with me were also not Confirmed.  I know the baptisms of both my nephews, in 1998 and 2007 are invalid.  The form was wrong in both, and matter in the second.  

The Confirmandi high schoolers wrote "a creative liturgy" which the Bishop used in 1974.  There was no oil used, but I recall processing outside in a conga line to the beat of bongo drums and a sitar.  There was a group photo with the bishop, then everyone went home.  Decades later, I requested a record of this and all that was found was a yellowed sheet of loose-leaf paper with penciled names  some checked, some crossed off, some with question marks.  This was stuck in the back of a large binder from the parish which has since gone out of existence.  The binder was in the basement of neighboring parish.  There is no record with the diocesan headquarters.  

At both baptisms, the words, "You are initiated a child of the Father, the Creator, the Spirit. Welcome to the family of God," were substituted.  At the 2007 baptism, a "eucharistic minister" sprinkled holy (?) water while the priest (?) said the incorrect words from his wheelchair.  He had broken both arms and legs in an auto accident, and was therefore literally unable to baptise anyone.

It's just as well on the baptisms because the children haven't entered a house of worship since.  They were raised "not-religious." They were baptized to appease an elderly relative whose house they were living in, free of charge.

What percentage of, say, Arian Baptisms are/were invalid?

Matter, Form, Minister, Intention...

"Don't think of Elephants..."

It's a trick question anyway, if unwitting; why? Because, sacramentally speaking, there's no such thing as a NO baptism, a Protestant Baptism, an Anglican Baptism etc., etc....

May as well ask about the validity of Atheist Baptisms.

Stolen goods are just that, stolen goods.

I must admit years ago I attended a Family baptism of a new born infant.

The Priest is known for his extreme liberalism and have long since left the Priesthood and
the church.

I remember that he used the following in the baptism:

I baptized you in the Name of the Father, the mother, the Son, and the Holy Spirit.

The infant who is one of my nephews grew up and is now a very radical leftist and atheist.

I get the impression that the Novus Or do is better about this now.  40% might be legit for the 70s but way too high nowadays.  Probably only 5% or less invalid now.