Would save 3% too.

$ echo "How Image Optimimization decreased my website's page weight by 62%" | wc -m

67

$ echo "How Image Optimization decreased my website's page weight by 62%" | wc -m

65

$ echo "scale=3; (67-65)/67" | bc

.029

Math checks out, sir.

But:

    $ echo "" | wc -m
    1

You probably want to add the -n flag to echo. It doesn't change the validity of the statement though.

bc; A new utility I did not know about, thanks! #themoreyouknow