The most common unemployment statistics only include people actively seeking employment. Since you'd 1) be actually willing to work and 2) have to interact with strangers to go on job interviews, it that wouldn't be considered a hikkomori.

Unemployed almost never includes retired people and 36.2% of those surveyed cited retirement as a trigger for social withdraw.

True, although I would have thought they fell outside the definition of unemployed as well as they aren’t seeking work.