Can you have gum disease without knowing.
Having regular dental checkups are important because you can have dental issue without knowing it. Many times cavities do not hurt until the get large enough to cause issues. The same goes with gum disease, since gum disease is not painful until later stages.
Also take into account that about 80% of Americans have gingival inflammation and that over 50% of Americans over 50 years old have periodontitis, yet only about 4% are getting treatment for gingivitis or periodontitis, it is a safe bet that most Americans have gum disease and do not know it.