Looking at some of the research studies I found on the net, apparently not too many users know about the Cntrl+F functionality. To quote the research study done by Mozilla
One relevant 7-day TestPilot study of about 69,000 Windows users
focused on Firefox’s user interface. Along with seeing how users
interacted with the navigation bar, their bookmarks, etc., the study
looked at how often people used keyboard shortcuts.
What we found is that about 81% of TestPilot users didn’t use CTRL+F
during the course of the study. While 81% is lower than the 90% in the
article, TestPilot users are usually more technologically experienced
than the general population, since they are largely Firefox Beta
users. When we look at TestPilot users who consider themselves
beginners, the percentage goes up to 85%. Therefore, our 81% figure
does not belie the Atlantic piece.
In addition, those who use CTRL+F on average use keyboard shortcuts
twice as much as those who don’t, even when we ignore those people who
don’t use any keyboard shortcuts at all. This implies that people who
use CTRL+F are more comfortable with keyboard shortcuts in general.
The only keyboard shortcut the users who use CTRL+F lag behind in is
Full Screen, or F11.
The referenced article in this above extract is an article in The Atlantic which states that 90% of users dont know how to use CNTRL+F
This week, I talked with Dan Russell, a search anthropologist at
Google, about the time he spends with random people studying how they
search for stuff. One statistic blew my mind. 90 percent of people in
their studies don't know how to use CTRL/Command + F to find a word in
a document or web page!
So it seems like a vast majority dont really use that as an search option though I'll be curious to see how many other keyboard shortcuts were known to users as opposed to this.
Edit: I recommend reading this research article which talks about the how the use of keyboard shortcut usage is perhaps influenced by social factors and the amount of time spent on the computer. To summarize the article
The current research also found no relationship between years of
experience with a computer and the use of KBS, however, we did find a
relationship between use of keyboard shortcuts and hours spent using a
computer per week. These findings suggest that the amount of time
someone currently spends on the computer may be a more predictive a
factor for the efficient use of a computer program than the number of
years or level of expertise a person has with a particular program.
