If you look at business travel a good portion of visas are approved.
If you look at single female the refusal rate is extremely high because of the trafficking issues in prostitution and massage.
Sure if you pull all applicants together I could see the percentage of refusal being in the 20+ percentile.
I would bet a years salary that they might approve 1 out of every 200 single females and that this category is the highest rejection category with single males under 35 the next.
The US does not want women in prostitution nor do they want male overstays working unauthorized.
I have a friend that works in one of the Asian embassies (not Thailand) and he has pretty much explained how applications get processed. And there are so many variables one of which is visa return status for prior holders. When they have more overstays for a period they reduce approvals. There is an unofficial cap which contributes to future approvals.
And let me add that this is one of those situations that knowing someone inside really does nothing because in many cases the approval is not done at the local level.
And I was being sarcastic with the questions in my post.