Interesting q for experts and experience members

Dear all,

I am making an internal report and am stuck on one aspect. I tried to check with my friends but not getting very satisfactory answers.. Please help, it would be highly appreciated..

I want to know type of business (types, like, construction, computer hardware, salons, printers, restaurants, etc etc):

1. that are almost always (>90%) never involved in double accounting (black accounts for tax invasion)
2. that are almost always (>90%) involved in double accounting (black accounts for tax invasion)

More examples, the better.

[note: i don't need name of business, just type/category.]

Thanks in advance.

Regards,
Kinjal Desai.