This last year at 87kg I kept a more accurate log of sails and boards I used, Heres my sail sizes and the percentage of use they got.
2016 Blade 4.2m 7%
2016 Blade 5.0m 27%
2016 Blade 5.3m 24%
2016 Blade Pro 5.7m 42%

15% of the 5.7m usage it was not big enough and I grovelled.

I was surprised how much use my 5.0 got and a bit diappointed how much my 5.7 got as its my light wind sail. I'm not sure if I need to make changes to sizes or are my results a reflection of the wind strengths.
I'm keen to see other nerdy records.