The MFGB's membership increased by 30% in its first year and by 1890 its member federations had 250,000 members. The Northumberland Miners' Association and the Durham Miners' Association initially refused to join but did so in 1907 and 1908. Most of the MFGB's founding officials were still in control in 1910 by which time the membership was more than 600,000. Membership peaked in 1920 when it had more than 945,000 members. In 1926 the membership dropped to 756,000 and had declined to about 530,000 in 1930.