Welcome to the Forum. I'll try to help. Let me first endorse the comments made on the Community site. While there is ongoing, legitimate scientific debate as to whether your body is totally free of HPV DNA once visible infection is gone, the bottom line is that now, after 20 years, there is no reason to fear that the virus might either reactivate or cause you or sex partners harm. Like you, I am confident you are not at risk for recurrence of your genital warts.
As for your question as to what proportion of persons have the HPV types that cause genital warts and what proportion of those are symptomatic, this is more difficult to determine. Current estimates that at least 10% of adults will have genital warts at some point in their life and it is likely that additional persons will have the infection but not visible warts. My guess is that overall, over the life course somewhere between 12 and 20% of adults will have or have had infections with the HPV types (6, 11) which cause most gentile warts.
I hope this response is helpful. EWH
Very helpful, thank you very much for your response, it is much appreciated.
oops, I just realized that something in my first paragraph might not be clear. I meant that I feel confident that genital warts will NOT reappear, since I had them over 20 years ago.