since reloaded game current version, no one knows except game owner as far I know. The old game according to some old players, they knew the rate been public or something like that (not sure). It is not just bunker or magma but those are similar to other parts very rare to obtain passing years, and some get them fast. Every acc works a bit different. I got a magma granted passing 2 years including a bunker. I have few others because old game owner summertime sale in the forum for forum members and another for every player in regular sale back in 2020 and no more since then.