It's hard to accurately measure adoption level mostly because of the decentralised nature of Bitcoin, but looking at the transaction volume is a really bad approach. One individual sending money back and forth can generate tremendous volume (similarly with exchange moving their funds between hot wallet and cold storage). Same goes for transactions count (if you are moving big enough funds you don't have to pay fee), plus there are things like satoshidice or reddit tip bot that tend to move towards off-blockchain transactions now.

> One individual sending money back and forth can generate tremendous volume

Which is what the "days destroyed" measurement looks to compensate for https://blockchain.info/charts/bitcoin-days-destroyed https://en.bitcoin.it/wiki/Bitcoin_Days_Destroyed

Yeah, it's a very nice metric. But I don't think it's related to adoption. I mean if bitcoin is used as a currency and quickly changing hands you wouldn't expect many "bitcoin days destroyed" (as opposed to when e.g. exchange is reorganizing its funds)

You would actually expect to still see it climbing week over week though with the odd spike.

That looks like the price spiking and lots of trades happening, or alternatively a major individual player moving their coins around.

It definitely says nothing about consumer adoption.

Moving coins is almost-free, but not 100% free. Why would a major player want to lose money?