While the Socialist Labor Party used a monthly dues stamp system for collection of its organizational dues, it was for the entire duration of its early period extremely reluctant to release stamp sales figures. Unemployed workers did not pay monthly dues and this fact to some extent colored the organizational decision not to make stamp sales the benchmark of the group's membership size. Archival research is needed to construct a meaningful series of paid memberships. Numbers below are memberships claimed by the organiziation, generally at official gatherings, and should be regarded as somewhat suspect until concrete archival numbers are discovered and published.
1876 ------2,978 (claimed)
1877 ------"about 7,000" (claimed at Dec. 1877 Convention)
1878 -------X,XXX -----
1879 ------1,500 (estimated)
1880 -------X,XXX -----
1881 -------X,XXX -----
1882 -------X,XXX -----
1883 ------1,500 (estimated)
1884 -------X,XXX -----
1885 -------X,XXX -----
1886 -------X,XXX -----
1887 -------X,XXX -----
1888 -------X,XXX -----
1889 -------X,XXX -----
1890 -------X,XXX -----
1891 -------X,XXX -----
1892 -------X,XXX -----
1893 -------X,XXX -----
1894 -------X,XXX -----
1895 -------X,XXX -----
1896 -------"5,000 to 6,000" (claimed)
1897 -------X,XXX -----
1898 -------X,XXX -----
1899 -------X,XXX (regarded by Hillquit as the peak membership year)
1900 -------X,XXX (year of membership decline due to party split)
1901 -------X,XXX -----
1902 -------X,XXX -----
1903 -------X,XXX -----
1904 -------X,XXX -----
1905 -------X,XXX -----
1906 -------X,XXX -----
1907 -------X,XXX -----
1908 -------X,XXX -----
1909 -------X,XXX -----
1910 -------X,XXX -----
1911 -------X,XXX -----
1912 -------X,XXX -----
1913 -------X,XXX -----
1914 -------X,XXX -----
1915 -------X,XXX -----
1916 -------X,XXX -----
1917 -------X,XXX -----
1918 -------X,XXX -----
1919 -------X,XXX -----
1920 -------4,000 (approx.)
1921 -------X,XXX -----
1922 -------X,XXX -----
1923 -------X,XXX -----
1924 -------"About 2,500 in good standing" (claimed)
1925 -------X,XXX -----
1926 -------X,XXX -----
1927-28 ----X,XXX- // 46 per month ave. exempt---
1928-29 ----2,000 (claimed approx.) // 45 per month ave. exempt
1929-30 -----no figures released or claimed // 55 per month ave. exempt
1930-31 -----about 5% fewer than the FY1931-32 figure (Petersen) // 141 per month ave. exempt
1931-32 -----"around 2,500" ("including those exempted and roughly estimating the number of those who do not buy dues stamps and do not ask for exemption stamps" --Petersen) // 322 per month ave. exempt
1928-32 exemption figures calculated from published physical exempt stamp statistics in Eighteenth National Convention Socialist Labor Party, April 30-May 2, 1932: Minutes, Reports, Platform, Resolutions, etc. (NY: National Exectuvie Committee SLP, 1932), pg. 51. The SLP's fiscal year began on April 1. These figures should be regarded as reliable. National Secretary Arnold Petersen failed to provide either stamp sales statistics or a reliable means of calculating membership via financial data -- doubtlessly an effort to obscure a decline in paid memberships over the four year interval. This premise is made increasingly likely by the rapid escalation of exempt stamps for unemployed members.
1932-33 -----1,257 paid + 628 exempt (= 1,885)
1933-34 -----1,605 paid + 708 exempt (= 2,313)
1934-35 -----1,776 paid + 562 exempt (= 2,338)
1935-36 -----1,981 paid + 552 exempt (= 2,533)
1932-36 figures calculated from published financial and physical exempt stamp statistics in Nineteenth National Convention Socialist Labor Party, April 25-April 28, 1936: Minutes, Reports, Platform, Resolutions, etc. (NY: National Executive Committee SLP, 1938), pg. 70. The SLP's fiscal year began on April 1. These figures should be regarded as reliable.
1969 --------- 697 (approx., based on net change cited in Karp report)
1970 --------- 630 paid + 37 exempt (= 667)
Stated dues stamp sales in the report of National Secretary Nathan Karp in National Executive Committee Session, May 1-2, 1971: Minutes, Reports, Etc. (NY: National Executive Committee SLP, 1971), pg. 23.