Niven is an uncommonly occurring given name for males but a very prominent surname for both adults and children (#19272 out of 150436, Top 13%). (2000 U.S. Census). Shown below is the baby name popularity of Niven for boys.
So, what length is the right one for a book? The average nonfiction book, if such a thing exists, runs about 50,000 to 75,000 words, but this can vary depending upon category. Biographies, for example, can run 200,000 words.
Divide this into total revenue (again, $910m) and we get an average revenue per Amazon ebook in 2012 of $484. The last step is to estimate out how much the authors are making from these sales. What we need to know is how many of those 1.87m titles are priced under $2.99 (35% royalty) vs. $2.99 and up (70% royalty).