Servants and Socio-economic status

I have been wandering about the connection between the presence of  ‘servants’ and the socio-economic status of a household during the late 19th century in Norway.  From the videos Jules has posted on the blog one can see a very clear connection between enormous wealth and servants.  However, I wander how wealthy one needs to be to have servants in Norway in the late 19th century.  Answering this question gives us insight into the relative wealth of the Helmer household. Furthermore, I wander how long the Helmers have had household help.  Even during their economic hardships would they have still employed Helene and Anne-Marie?