The book mentioned, David Barrett's World Christian Encyclopedia, as the primary source of the figure of "33,000" or "20,000" or similar figures we Catholics talk about seems to define "denomination" in a slightly unorthodox fashion (no pun intended).
Denomination is defined as an organization within a single country. This means that if the Roman Catholic church is in 234 countries, it would have a at least 234 denominations. Conversely, To say the Roman Catholic church has 239 denominations in 234 countries, is a conclusion that seriously misreads the data. On the other hand, the fact that there are 8848 denominations in the Protestant column, does not mean there are 8848 Protestant denominations as Catholics suggest. If you divide 8848 by the 237 countries, you come up with a figure of only actual 37 denominations in 237 countries.
I don't quite understand the logic here, especially the last sentence, but that's ok. The tables here are the useful part, and give us a fair idea of the true number of denominations, in common parlance.
Note, the divisions in "Roman Catholic" are the different "rites", so this is not a "denominational" division in the theological sense. Anyone with a basic understanding of the Church knows this.
Similarly for the Orthodox Church. (I imagine, but perhaps an Orthodox adherant can shed some light on it further).
However, if we count the actual names underneath the tables called, "Anglican", "Protestant", and "Independent" (and ignore those under the "Marginal" table), we come to a grand total of 242 separate and distinct "denominations" (at least what we, in theology would call "denominations".)
If we delete the "Independent" (if someone protests, again no pun intended, that the "Independent" denominations aren't really PROTESTANT denominations), then we are still left with 42 separate and distinct denominations.
42 denominations, all claiming to have the whole truth (obviously, or else why separate from the others?) 42 all claiming to be led by the Holy Spirit.
The message here is clear: Whether the number is 30,000 or 42, there STILL exists a clear distinction between churches, (Catholic included), ALL of which claim to be guided by the Holy Spirit.
So the ultimate question still remains: Is the Holy Spirit the author of confusion? If not, then a Christian's task is clear: He must choose ONE of those churches in the list above, and ALSO MUST believe the rest are, at least, not fully true. If not, then the Christian is supporting the notion that the Holy Spirit is the author of confusion. There's no getting around that.
Let's not loose sight of the forest because of the trees. It's really irrelevant if there are 30,000 Protestant denominations or 42, or even only 2. As long as there are at least TWO that are CLEARLY different in their DOCTRINE, then the point above is valid.
I am a Christian plain and simple, i.e. I do not choose from that or any list.
My point was hyperbole doesn't win arguments.