I have some historical statistics on my Slatington News project site.
Population Growth of Slatington, Pennsylvania from 1870 to 2010
Population of Slatington, PA in 1870 According to Place of Birth
1870 Population of Slatington, PA over 18 by Place of Birth
Population of Slatington, PA in 1880 According to Place of Birth
1880 Population of Slatington, PA over 18 by Place of Birth
Population of Slatington, PA in 1900 According to Place of Birth
1900 Population of Slatington, PA over 18 by Place of Birth