If you have 1 million coins and only one person is willing to sell 1 coin and they sell it (or ask to sell it) for $100 then you have a market share of $100 million dollars. It's too variable an indicator to be objective.
An interesting comparison would be plotting the USD market value of coins over time rather than comparing to BTC. BTC and the other alternate coins have been around a bit longer then TRC. Were the BTC and LTC markets worth 2,478 BTC * $70/BTC = $173,460 a mere four months from introduction?
I can't argue with that rebuttal, tgsrge. You've convinced me. I'm selling off my TRC.