In what year was labor day declared a national holiday?

1894/Labor Day pays tribute to the contributions and achievements of American workers, and Labor Day 2018 occurs on Monday, September 3 (it's traditionally observed on the first Monday in September). It was created by the labor movement in the late 19th century and became a federal holiday in 1894.

explanation:

an oligopoly is a term used to clarify the structure of a particular market, industry, or organization. a market is considered oligopolistic or amazingly focused when it is shared between a few companies.

i believe it was the shinto