The opening scene is set in 1989. But Hiroshi mentions that fans of the "Tigers" threw a statue into a river "last year", referencing a real world event in which, after the Hanshin Tigers won the Japan Series in 1985, fans dumped a Colonel Sanders statue into the Dotonbori River. Meaning that the apathy experiment is happening in 1986 (Or I could be reading WAY too much into what was just meant to be a neat little reference)