I am working to complete my Masters thesis and I am confused on which sample I should use for different models.

My original dataset, after restricting age to the working population, has 80,000 observations. I plan to estimate two models:

First model investigates wage equations for workers in different locations:
1. reg wage x1 x2 x3 if location=="England" ; obs: 21000
2. reg wage x1 x2 x3 if location=="Wales" ; obs: 18000
3. reg wage x1 x2 x3 if location=="Ireland" ; obs: 22000

Second model investigates wellbeing equations:
1. reg wellbeing x1 x2 x3 x4 x5 x6 if location=="England" ; obs: 7000
2. reg wellbeing x1 x2 x3 x4 x5 x6 if location=="Wales" ; obs: 3000
3. reg wellbeing x1 x2 x3 x4 x5 x6 if location=="Ireland" ; obs: 6000

Since my second model has more control variables, there are less observations.

My question is, when I describe my sample size in the descriptive statistics section, do I describe my sample size as 80,000 observations even though the majority are not used in the regressions? Should I consider dropping some variables with missing values? Thanks in advance.