That last part is why I think some states require you to buy a license for application purposes.Let's talk trend analysis from your link:
License sales:
1958 - 14,138,182
1971 - 15,977,873
1990 - 16,257,074
2000 - 15,045,294
2007 - 14,726,427 pre recession
2010 - 14,447,040 post recession
2015 - 14,843,895
2017 - 15,486,123
The overall trend is downward since 1970. I'd call 2017 an economic bubble. Furthermore, states are gaming the license sale system to maximize Pittman Robertson reimbursement.