<p>
If students are getting much better grades than before, where a C was average, then it must mean one (or more) of the following.</p>
<ol>
<li>The students are much smarter.</li>
<li>The teaching is much better.</li>
<li>The grades are much easier to get.</li>
</ol>
<p>I dunno about you, but I hardly think the intelligence of the population has raised much or that teaching methods have advanced. That leaves easier grades as our most likely culprit.</p>
<p>There are several reasons why grades are easier to get, and why this is bad; just google grade inflation and you will see a wide variety of papers and opinions on the subject.</p>