Marketing questions for financial books for businesses...

The business books that I write are targeted to a specific niche or audience, I mean how many people are going to buy a book on how to start their own collection agency? 
Though many business owners will buy a book on how to limit credit risk
and get paid from past due customers. 

 I sorted my list of customers who have purchased my books to date and this is what I came up with:

Highest number of book orders

 CA                   176

NY                  120

FL                    119

TX                   99

GA                   80

PA                   73

IL                     72

OH                  61

 Lowest number of book orders

 AK                  3

MS                  3

DC                   2

VT                   4

WV                  4

This is interesting to me, I am in NH and only had 38 sales to customers in NH, where I do most of my marketing, the surrounding area shows even less in sales, for example I sold only 29 books in MA, 4 in VT, 3 in RI,
and 11 in CT. 

I am trying to figure out how to make more sales with this information, and am wondering if I should pick up my marketing in the states where I made the most sales, CA, NY, FL, TX and GA.