the bellow link might be helpful in understanding the data storage in QlikView
Qlikview i.e. the .qvw will provide you 10X compression on the data. But the Qvd will not be compressed!! its size is directly depends on the size of the data your having. we can optimize the qvd's not the compression.
Sorry for the delayed reply.
For example if u have a sales data file of 50MB, it can be compressed to 10MB
NOTE: It all depends on the unique values u have in that table
Read this link.
It will be good!!