In 2020, a Detective Comics No. 27, featuring the first appearance of Batman, was sold at auction for $1.5 million. The comic book was originally sold in 1939 for $10. What was the annual increase in the value of this comic book? Note: Do not round intermediate calculations and enter your anwer as a percent rounded to 2 decimal places, e.g., 32.16. Answer is complete but not entirely correct