In the U.S., an estimated 25–50 million cases of the flu are currently
reported each year — leading to 150,000 hospitalizations and 30,000–40,000
deaths yearly. If these figures were to be estimated incorporating the rest of
the world, there would be an average of approximately 1 billion cases of flu,
around 3–5 million cases of severe illness, and 300,000–500,000 deaths
annually.
Based on these numbers I would say that we are always in a pandemic.