Help Needed!!!

#1
I have quarterly income data for 10 household spread over 20quarters. I have to calculate the numbers of days it took for a household to go from one decile to another over all deciles (10 to 1); so as to find out where where the big changes occured - the most rapid or slowest.

An issue which I would like to discuss here is: let us say for a household X, it took 5 quarters to move from Decile10 to Decile9; then another 2 quarters to move from Decile9 to Decile8; then another 1 quarter to move from Decile8 to Decile10 and finally another 2 quarters to move from Decile10 to Decile9. In this case what would be time taken by household X to move from Decile10 to Decile9?

Hope I am clear.:)
Bye