My Neck is Tingling, from Nigel Davies
The hairs on the back of my neck stand up every time I hear 'positive drift' because the stuff they're being measured against (currency) is also in a state of constant flux.
It's amazing what a shilling (now 5 new pence) was worth a couple of hundred years ago; factor in various technological revolutions and huge population growth over the time this 'drift' has been measured and I'm not sure you can reasonably extrapolate it forward.