The Buck Stops Here

Paperlate
I'm sorry but
There's no one on the line
--Genesis

Put the below graph together using data from the BLS site.

By my calcs, $100 in 1916 is now worth about $3.50. And given the tortured state of our CPI statistics, this is likely a conservative estimate.

The Federal Reserve Act was passed in 1913, although the Fed didn't get active till 1916ish. The 16th Amendment was also ratified in 1913.

We should also note that, although CPI stats were not kept prior to the mid 1910s, estimates I've seen suggest relatively stable USD purchasing power during the pre-Fed 1800s.