Sometimes I see the figure of 7.8 quoted, and sometimes 8.0 and occasionally see 8.5 (for diabetics in remission).
Different organisations and different countries use different figures in relation to diabetes, they often use different units as well.
For example the USA uses different units, but even when converted their threshold for Pre-Diabetes is lower than ours here in the UK, which partly explains why they have a higher proportion of pre-Diabetics than we do. Though of course many diabetics and pre-diabetics are waking around un-diagnosed!