In the following decades, New York strengthened its dominance of the financial and banking industries. Manufacturing continued to rise: Eastman Kodak founded in 1888 in Rochester, General Electric in Schenectady, and Endicott-Johnson Shoe Company in the Triple Cities are some of the well-known companies founded during this period. Buffalo and Niagara Falls attracted numerous factories following the advent of hydroelectric power in the area. With industry blooming, workers began to unite in New York as early as the 1820s. By 1882, the Knights of Labor in New York City had 60,000 members. Trade unions used political influence to limit working hours as early as 1867. At the same time, New York's agricultural output peaked. Focus changed from crop-based to dairy-based agriculture. The cheese industry became established in the Mohawk Valley. By 1881, the state had more than 241,000 farms. In the same period, the area around New York harbor became the world's oyster capital, retaining that title into the early twentieth century.