To find out if Pugs were the top dog breed registered with the American Kennel Club in 1999, you would need to:
1. Check the American Kennel Club website: They likely have archives of their registration data. Search their website for information about the most popular breeds in 1999.
2. Contact the American Kennel Club: You can reach out to them directly and inquire about their registration records for that year.
I hope this helps!