Good question, and many good responses. I probably know a few, mostly older Catholics, as one other poster mentioned, who are 100%. I know a few others who THINK they are, but aren’t. But the vast majority, no. And there are several reasons for this.
First, many are not aware of what they are supposed to know or believe. I don’t mean the basic stuff, like attending Mass every Sunday and Holy Day and receiving the Eucharist, but the other stuff. I found a list of Catholic doctrines online, and I would bet that most Catholics, if asked to read the list, would respond to some of them: “I didn’t know that.”
Second, a majority do not abide by some of the rules or teachings of the Church, such as on the forms of birth control. But this is not a modern phenomenon, as we can see from the past centuries when the Church had to warn people about certain ideas, books, movies, etc. Or think about the directives about the Syllabus of Errors or Modernist thinking. The Church has had to work very hard over the years to keep or get people back on the right path. Not always with great success.
Third, as we can see from the various discussions on these forums, there is disagreement over what is an “orthodox” Catholic. Some say it is being in 100% communion with Rome and the Pope in their beliefs and actions. Others say that current Church leaders and doctrines are headed in the wrong direction, and want to follow the “ways” of an earlier time, prior to Vatican II. And there are others, probably the majority, who don’t really care who knows best on those issues, and just try to be the best Catholic they can, given the circumstances of their lives.
I find it interesting, and somewhat humorous, that so many of those who post here indicate their allegiance to a particular Pope, usually the current Benedict, JP II, or Pius X (or is it Pius XII, I get mixed up on that). That in itself tells you quite a lot about where they fit in the spectrum of Catholicism. Thankfully, I haven’t noticed anyone favoring a Pope like Alexander VI, or his uncle, Calixtus III.