|1860 U. S. Census, City of St. Louis, Missouri, 2nd Ward, dwelling 387, George Rothweiler household.|
This enumeration is slightly different. The oldest female in the household (the apparent wife Wilhelmine Rothweiler) is indicated as having an age of 29 1/2. Fractional years appear as part of the ages for other children on this census page, but Wilhelmine (actually Wilhelmina) is the only adult on the page with a fractional part of a year included as a part of her age.
I'm not certain how common this is, but I don't remember having seen fractional ages for adults on a regular basis.
Or may she was just "twenty-nine and holding."
[Wilhelmina was a first cousin to my gg-grandfather John Michael Trautvetter.]