A decline in the growth rate can be matched to the quarter military deaths for white southerners as well as extended absences of soldiers. Immigration from Europe, never of the same proportions as the north, was also interrupted. White emigration to other parts of the US is another, largely unknown factor. It is a wonder that the southern white population grew at all. As for southern Blacks, there was a great migration within the south as former slave families reunited as well as movement out of the south. There is also a question as to the census count of former slaves. They were no longer neat units who were counted by the information provided by overseers. The information provided was very interesting but statistical analysis needs to take take into account non-statistical factors along with raw numbers. Remember also that 2/3 of the military deaths were non combat related and must have spread diseases throughout the regions in which they passed. It was also a time when outbreaks of disease were common, even striking the White House. Might disease in the overcrowded wartime cities be more prevalent than the high peacetime rates? An intriguing subject, nonetheless. At the end of the day, I suspect all that would left is an estimate as McPherson and and others have done.