My personal opinion is that there will always be a need for physical analog money. The power goes out in Puerto Rico (hurricanes) and Manhattan (ConEdison) sometimes (just recapping the stories covered on NPR during my drive to work this morning).
That's very interesting. I wouldn't be surprised if the volume of physical cash is growing with a growing economy, but the fact that it's accelerating is unexpected. Do you have any links to learn more about this?
Is inflation speeding up, or are notes just retired more often?