The actual size of a sparse structure is the number of distinct combinations of its entities. This number is visible from the Entity function. Click the Entity icon then click the Sparsity tab.
The number of combinations of the sparse structure is shown in the Item Nr column.
Clicking on a sparse structure displays the list of InfoCubes versions that utilize the structure and the density.
Clearing all InfoCubes using a sparse structure clears the sparse structure too and resets the number of sparse combinations to zero.
The density is a measure of how much a sparsity is effective : a low level indicates that thankful to the Sparsity the Number of Cells is much lower that the total number of cells given by a non sparse structure.
A density close to 100 indicates that the sparsity is pretty useless as much as can affect the database performances uselessly.