Probably about 30-50 now, of the ones that have told me anyway, I expect that another third would be keeping it quiet.
About 1/3 of those confirmed ones are from NHS workers who likely caught it at work then passed onto every member of their household.
About 1/3 from mates in WhatsApp groups etc, most have been obeying the rules, very strictly, and have been working from home, but have young children which have been to nursery or school
Last 1/3 are people form work (very, very small company) and their immediate families, who have been breaking rules, think it's a hoax etc
Top 1/3 would be reduced if there was less cases, but come as a result of the below
Middle 1/3 would be reduced if the kids were not at school, and if people we not acting as per the below
Bottom 1/3 would be reduced if people weren't being dcikheads
All would be reduced if the government followed the science, not pretended to be following the science
All would be reduced if the government acted in a preventative manner, not reactive (slow reactive) manner