they represent about 1% of population (see https://asia.nikkei.com/Spotlight/Asia-Insight/Pope-Francis-Japan-visit-spotlights-a-safe-haven-for-Catholics https:/

they represent about 1% of population (see https://asia.nikkei.com/Spotlight/Asia-Insight/Pope-Francis-Japan-visit-spotlights-a-safe-haven-for-Catholics https://asia.nikkei.com/Spotlight/Asia-Insight/Pope-Francis-...), seems to me that "almost none" is bit strong :)