Task: Question Generation
Input (English): Passage: The Front refused to officially disclose the number of members that it had. Thurlow suggested that "the most reliable estimates" were those produced by the anti-fascist investigatory magazine Searchlight (magazine). Following its establishment, the NF claimed to have 4000 members in 1968, and in February 1974 a branch chairman claimed that it had 20,000 members. Fielding suggested that it probably had about 21,000 members in early 1975, of whom 6,000 to 8,000 were "paper members" who had not renewed their membership subscriptions but not officially terminated their membership. Searchlight claimed that from its origins with 4,000 members in 1968, the party reached a peak membership of 17,500 in 1972, which had declined to 10,000 in 1979, to 3,148 in 1984, and to 1,000 in January 1985. An estimate of party membership in 1989 put adherents of the Flag Group at about 3,000 and of the Strasserite faction at about 600. Thurlow noted that even at its peak in the 1970s, the Fronts membership was still only half the size of that of the BUF during its 1930s heyday.
Output (English): How many more members was the NF claimed to have in 1974 compared to 1968?