3.2) What is a National Banknote?

  After the US Civil War (1865-1935), the US government created
charters for private banks to print paper money which was backed
by the US Government.  There were a very large number of national
banks chartered from all over the USA (e.g. Nashville, Tennessee;
Key West, Florida; Bismarck, North Dakota; L.A., California).
Many people collect "nationals" and the prices have gone up
substantially (to around the 150 dollar level on average).