Some dates are likely incorrect. Most ads I obtained from Google Books searches of American Stationer and Geyer’s Stationer. Some were found online, and the date is that used by the person posting unless I could determine the actual date of publication. For example, not all of the ads touting the number of pens sold appear in chronological order based on the dates stated alongside the ad.
1886 
1887 
1887 
1887 
1887 
1887 
1887 
1887 
1888 
1889 
1889 
1889 
1889 
1889 
1890 
1890 
1890 
1891 
1891 
1892 
1893 
1895 
1896 
1896 
1899 
1902 
1904 
1904 
1905 
1905 
1905 
1906 
1906 
1906 
1907 
1907 and 1909 
1907 
1907 
1908 
1908 
1908 
1909 
1909 
1910 
1910 
1911 
1911 
1912 
1912 
1915 
1929 
undated 
undated, c1915 
undated, post 1903 
pre 1903, undated