In my opinion the days-destroyed thing is rather useless, let me explain why. Let's say someone has 1,000 bitcoins in one address which has not been touched for four years. Now, they spend a single satoshi out of it. The bitcoin days destroyed will be virtually nothing, but in reality the actual days destroyed are all 1,000 bitcoins, because the spend transaction, even it's just one satoshi, demonstrates that this address is no longer in hibernation. By virtue of spending anything out of that address the owner has declared that they are in active control of that private key and all of the coins associated with it; so, we can consider all of the coins as alive/active at that point.
My own tools report these statistics, I wish blockchain.info and other sites would display this much more meaningful information.
For what it's worth, I just gathered some statistics about the blockchain yesterday, including zombie/hibernating coins/addresses:
* To date there are 279,535 blocks.
* There have been a total of 30,720,691 transactions performed since day one.
* Those transactions are comprised of 67,717,755 inputs and 75,658,307 outpus.
* There have been 25,397,303 unique public key addresses ever referenced in the blockchain.
* Of these some 22,982,911 of those addressees have a zero balance and have been completely spent. Likely just used for intermediate purposes.
* That leaves just 2,41,392 unique public key addresses with a non-zero balance.
* Of those with a non-zero balance, 1,213,328 of them contain 'dust', balance of less than one millibit. [121btc]
* There are 942,085 addresses with a balance greater than one millibit but still less than one full bitcoin. [87,367btc]
* There are 157,632 addresses with a balance between 1-10 bitcoins. [399,921btc]
* There are 88,328 addressees with a balance between 10-100 bitcoins. [3,277,444btc]
* There are 11,576 addresses with a balance between 100 and 1,000 bitcoins. [2,776,270btc]
* There are 1,344 addresses with a balance of between 1,000 and 10,000 bitcoins. [3,047,203btc]
* There are 97 addresses with a balance larger than 10,000 but less than 100,000 bitcoins. [2,313,516btc]
* There are two addresses with a balance greater than 100,000 bitcoins. [255,455btc]
* 2,023,005 bitcoins reside in addresses which have been untouched in over three years.
* 3,488,959 bitcoins reside in addresses which have been untouched in over two years.
* 4,381,452 bitcoins reside in addresses which have been untouched in over one year.
* 6,144,924 bitcoins reside in addresses which have been untouched in over six months.
* 944,410 bitcoins are in addresses which have had active transactions in the past week.
* 2,401,321 bitcoins are in addresses which have had active transactions in the past month.
* 5,079,095 bitcoins are in addresses which have had active transactions in the past three months.
* 5,887,186 bitcoins are in addresses which have had active transactions in the past six months.
Hopefully this gives you a good idea how many bitcoins are active an in circulation from those which are sitting in cold storage.
It is important to note that these statistics are *not* based on transaction volume. This is based on addresses which are deemed active or inactive in the time period specified.
What I mean by this is if someone has an address that holds 1,000 bitcoins and they spend a single Satoshi, then that marks all 1,000 bitcoins as being 'alive/active' in that time period since the spend transaction indicates that the wallet/address is 'alive'.
Are your tools available somewhere?