Google is your friend. I googled "speaker wire performance chart" and here's one of the thousand or so charts I got.



This looks like it has some pretty important information until you look at the last data point on the chart. It tells us that a signal will be reduced by only 1.3 dB after going through a hundred feet of sixteen gauge wire (we have to assume they're smart enough to run that signal through two hundred feet of wire, that is, a hundred feet out and a hundred feet back. That's pretty good but all the wires tested perform better.

Also note that the article states these figures are for eight ohm speakers. Insertion loss would be greater for four ohm speakers.