Here's why:
* No Centralized Tracking: There's no single, official source that tracks all anime viewership worldwide.
* Streaming and Physical Media: Viewers access the show through various platforms like Crunchyroll, Netflix, Hulu, Blu-ray, DVD, and more. Each platform has its own audience and tracking methods.
* Regional Differences: Popularity varies greatly depending on location. Sword Art Online is extremely popular in Japan, but its popularity may differ in other countries.
However, we can say that Sword Art Online is incredibly popular:
* High Sales: Anime Blu-ray and DVD sales are consistently high, indicating a large fanbase.
* Streaming Views: Streaming services like Crunchyroll often highlight the show's popularity.
* Critical Acclaim: The show has received positive reviews and critical acclaim, contributing to its wide appeal.
* Merchandise and Fanbase: The show has spawned numerous spin-offs, games, merchandise, and a large, active fan community.
While we can't pinpoint an exact number, it's safe to say that Sword Art Online has a large and dedicated following worldwide.