Let's use a neutral place just outside Manchester to judge.........The Bishop Blaize.....Yes...that salubrious establishment in the upmarket Greater Manchester suburb of Stretford.
Late last year, I was treating the missus to a slap up meal and a pint of cider - £6.50 for burger and drink - I know I spoil her, but a mans gotta do what he gotta do.
There were about 25 people in there - of the people I knew from local area, I counted 7 City fans (4 go to matches), 7 United fans (1 goes to 2/3 matches a season) & 2 Spurs fans (Spurs were on the tele that night).
So - if we take that as a demographic of the whole of Greater Manchester....
Population 2.8million - that means there are 784,000 City fans (448k go to matches every week) and 784,000 United fans (112k go to matches 'sometimes') in Manchester. Surprinsingly, there are 224,000 Spurs fans and 1,008,000 who don't care about football or aren't from here.
I think you shall find this study is pretty darn scientific, and if I weren't so humble I would probably expect to be nominated for a Nobel.
Of the 6 United fans who don't go to matches - they often mention empty seats at the Etihad and have valid reasons for not going to the games such as "it's on the tele", "too hard to get a ticket" and "I'm not paying £50 to watch that sh*t" or simply "can't afford it" or "I've got work". Of course, those same excuses can't be allowed if you are blue.