It’s somewhat hard to know how many informants the stasi had because of the destruction of records. Wikipedia suggests that this could have been as high as 500,

It’s somewhat hard to know how many informants the stasi had because of the destruction of records. Wikipedia suggests that this could have been as high as 500,000 (something like 1 in 30 people) or up to 2 million (something like 1 in 7) if one includes occasional informants