It's hard to know if the stats are reliable, because (just like today) people of color were systematically undercounted once they were no longer considered property who could be valued and turn up in wills. The town history was from Western Massachusetts, where the Sedgwick family's former slave "Mumbet" petitioned for freedom, leading to the end of slavery in Massachusetts. In Connecticut (including my home town), even after slavery was abolished, there was a literal "grandfather clause" that said those who were born enslaved would have to stay that way unless they--or someone else--could buy their freedom. This means there were still enslaved persons in Connecticut into the 1840s. Why didn't I know that before this year?