My best ever has been 78 hours straight 100% in my 4-7 target range, but that was a rare and beautiful thing ruined by a totally-worth-it weekend away! It’s usually around 75-80% in range.
Crunching my numbers over the last three months, I have an average BG of 5.9mmol with a standard deviation of ±1.4 and a glucose variability index of 1.17 - while an HbA1c just gives a three month average, the SD and GVI give an indication of how much it fluctuates - the hypers and hypos. A GVI of one would be a completely flat line.