It's about one-and-one-tenth times the number of Submarines in the US Navy.
In other words, the count of Submarines in the US Navy is 0.910 times 78.(a.k.a. Subs) (includes all types, all classes) (2015 figures)
It's about nine-tenths the number of Keys on a Piano.
In other words, 78 is 0.890 times the count of Keys on a Piano, and the count of Keys on a Piano is 1.10 times that amount.(Moden layout; A0 to C7)
It's about three-fourths the number of Wolves in Yellowstone National Park.
In other words, the count of Wolves in Yellowstone National Park is 1.330 times 78.(a.k.a. Henihco'oo; a.k.a. Héetíhco'oo) (December 2014 figures; Wyoming Park area)
As of the 2014 population count, there were 104 wolves living in Yellowstone National Park, in twelve packs. All of the wolves now living in the Park are thought to have descended from the 66 wolves (re)introduced into the Park in 1995-96.
It's about one-and-two-fifths times the number of Countries in Africa.
In other words, the count of Countries in Africa is 0.710 times 78.(2016 figures) (sovereign states recognized by the UN only)
It's about two-thirds the number of Elements on the Periodic Table.
In other words, 78 is 0.6610 times the count of Elements on the Periodic Table, and the count of Elements on the Periodic Table is 1.510 times that amount.(a.k.a. Periodic Table of the Elements, a.k.a chemical elements) (confirmed elements as of 2016)
From element number one, hydrogen, to element one-hundred eighteen, ununoctium, there are 118 confirmed elements on the Periodic Table. Ninety-four of the elements exist in nature, and the remaining twenty-four have only been synthesized in labs (not having occurred naturally in the time since scientists have begun researching them)
It's about one-and-three-fifths times the number of Teeth in a Great White Shark's Mouth.
In other words, the count of Teeth in a Great White Shark's Mouth is 0.630 times 78.(Carcharodon carcharias) (average; including developing rows)
A Great White Shark has 48 exposed teeth on their upper and lower jaws. Behind these exposed teeth are developing teeth — up to 300 in about 5 rows. The sharks will continuously lose and replace the exposed teeth throughout their lives.
It's about three-fifths the number of Union Stations in the United States.
In other words, 78 is 0.5780 times the count of Union Stations in the United States, and the count of Union Stations in the United States is 1.730 times that amount.(a.k.a. Union Terminal; a.k.a. Joint Station; a.k.a. Union Depot) (2016 figures)