This is actually suprising to me. I started out as a self taught programmer in middle-school. Very early on I ran into performance problems, and had to spend a fair amount of time making code efficient. I did, and still do, only explicitly try to make code efficient after I see it is a performance issue, but I wonder how anyone can do a large amount of programming without running into them.

Also, even if you never thought of efficiency, or algorithms. If someone describes binary search to you and you cannot implement it, you are still learning to code. If someone asks you to write an efficient search algorithm, I can see those types of people missing it (especially when you consider the fact that for the general case you also need an nlog(n) sorting algorithm.