I am not sure accademic records are kept about the occurance of similar Fingerprints (I have not seen any published data).
Trying to deduce the information might also be difficult. The reasons being that identification and cataloguing are different (almost) unrelated excercises, and it's possible that fingerprints are out of the scene time line, imported on objects or even fake.
For a positive identification to be made an "expert" has to view the partial / finger print recovered at the scene and then compare it to a (suposedly) good copy of the suspects actual print (this would be like having the image of the print stored on the Bio Card compared to the real finger on the scanner).
For cataloguing, various prominent features of the fingerprint are entered into a database (this was once done by experts but is now being automated).
Likewise the scene fingerprint is coded and a search run, the DB returns likley matches (this is like storing a hash of the fingerprint on the ID card then rehashing the real finger on the scanner and making a comparison with the hash).
The likley matches should then be (if possible) positivly identified prior to the fingerprint becoming considered for evidence (this would not be possible if the ID card only stores a hash).
I have been told that it is not unknown to get hundreds of likley matches on a partial scene fingerprint (not surprising). Also that likley matches can often be substantialy different when viewed for positive identification (again not surprising, one expert might consider a feature more prominant than another).
There have been a number of cases where "positive identification" has not obtained a conviction. Usually this is due to the accused being able to prove beyond doubt that they could not have been at the scene at the time required.
The problem with this is it does not rule out a valid fingerprint left at the scene at some other time or imported on an object, so does not argue the case for similarity between positivly identified fingerprints.
It also does not rule out faked fingerprints the ability to do this was mentioned many years ago in a Sherlock Holmes story.
I have made fake fingerprints when I was a youngster (over a quater of a centry ago ;) with,
1, the red wax from Edam Cheese (for the mold)
2, Rubber Solution glue (for the fake skin)
3, light machine oil (as the mold release)
4,a pair of surgical rubber gloves to bond the fake skin fingerprint to.
5, A little chicken fat to make the print
You also need the finger of the person whose print you are going to fake to take an impression with the wax.
From this you can see the technology to make fake fingerprints is not rocket science and can be done by the kid next door if given the right idea and access to the fingers of the "identity victim".
Also see past Cryptogram and "Gummy Fingers" where a Prof. worked out a way using PhotoShop and UV PhotEtch Printed circuit board material to make a mold from the photo of a fingerprint.
So you have several problems that are going to cloud the issue of finding out how many fingerprints (or parts) are similar in the real world.
Likewise DNA BioID may suffer from the same issues. The curent method of DNA comparison is to,
1, get a DNA sample
2, chop it up into short lengths with enzimes
3, produce millions of copies from the choped up pieces
You do this for both the scene DNA and the suspects DNA. You then make the comparison. On the face of it it's easy to belive the 4 billion to 1 or whatever the latest figure is that is quoted.
There are two problems with this, The first is are the arguments about the probability correct, the second is is it possible to fake somebodies DNA so the above test is positive for your identity victim.
In the early days the FBI kept a DB of DNA which was made available to accademics, there where reported cases of "duplictes" this was put down at the time to "data entry errors". Also there was a story doing the rounds that DNA from an Amoznian Indian gave a positive match against an entry in the FBI DB.
So there may be a question as to what the probability realy is of a match after the test (ie is the test used responsible for duplicates). Only when a very large number of people have been tested can we start getting an answer to this.
The second problem is "can you fake somebodies DNA", the answer to this depends on who you ask and how you ask them the question.
Usually you are told "It is not currently possible to clone human DNA in a meaningfull way", which indicates a fluffed answer to a fluffed question.
If you asked, "If I had somebodies DNA and I know what enzimes and replication methods are used for the DNA testing by the Lab, can I use the same enzimes and replication to produce vast quantities of their DNA strands". The answer to this question is usually yes.
If you then ask, "Are the strands stable with regard to time and temprature and other environmental factors if suspended in an apropriate solution" you will get a quite complex answer which varies upon who you ask, but is often yes with conditions.
If you then ask "If a small quantity of this replicated solution is accedently present when the Lab performs the test on the scene DNA is it going to effect the result". Again the answer is usually yes.
If you then ask "If there was no compleate DNA present in the test, just the strands would the test show positive for the person whose DNA you replicated and put into suspension" You usually get a strange look on the persons face and a fluffed answer.
I have not seen any published papers on this so it's possible that nobody has actually done any significant reseaurch yet. I susspect that if they did the answer would come back with a very qualified "Yes it's possible to fake a positive test using somebodies replicated DNA"