That 1% is a lot in my opinion, taking into consideration this is just a corner of the glacier, I guess there maybe in total 5% lost..
I wouldn't be surprised if it is more like 2M BTC lost. In the first year+ of Bitcoin's existence (during which almost 2M coins were mined) it was nothing more than an interesting experiment. The coins were worthless, and people treated them as such. I mean heck, the first known monetary valuation wasn't until Lazlo's pizza, which was mid-2010, 1 and a half years after it started. Not to mention than Satoshi himself mined a good 1M BTC, and I don't expect those will ever move.
Just my best guess on it. I'd be willing to bet that 10 years from now, there will be at least 2M coins that haven't moved between now and then.