Their numbers are minuscule at best. And the "merchants" you're talking about come primarily from gambling industry and bitcoin mining equipment production. I'm not taking into account somebody selling a Tesla car here or buying a house there for bitcoins. These cases are sporadic and far in between...
Why are you putting merchants in brackets? There's more than you think and more are popping up every day. There's quite a few big developments happening here in the UK already. I reckon the rate of businesses accepting bitcoins next year will be increasing quite dramatically. It's early days for Bitcoin/crypotcurrencies, but it's obviously making waves.
I've heard that more than half of bitcoin transactions come from some gambling site, don't quite remember its name (maybe SatoshiDice?). It is not the number of transactions that actually counts but rather volume transacted, but still it is no more than idle talk really unless we have accurate figures at our disposal...