Note: In 1900 Peter and Mary were living with Mary's mother, Selina Guthrie in Gallipolis, Ohio. Peter's occupation was "printer." They were very young and had been married for one year.
By 1904 the Pritchetts had moved from Gallipolis to Washington DC and their daughter Lucy had been born.
In 1910 Peter was 31 years old and Mary 29. Peter's occupation was a "stereotyper" working in the government. I conjecture that a stereotyper was the equivalent of a dictaphone typist.
In 1920 Peter and Mary were living on their own in Washington. Peter was 41 and Mary B. 37.