Good evening, guys. I'm currently working on a gravity model with PPML estimator. Here is the thread: I'm using a book from Yotov et al that has a formula for fixed effects. I'm only using exporter fixed effects and getting the same results for all the variables (sum equals 100). Can someone please tell if its correct?

the commands for PPML: ppml exp area dist population gdp gdpc mercosul landlock border

commands for fixed effects: egen exp_time = group (exp year) ; tabulate exp_time, generate (EX_FE)

this is part of the result:

832 | 1 0.04 30.78
833 | 1 0.04 30.82
834 | 1 0.04 30.85
835 | 1 0.04 30.89
836 | 1 0.04 30.92
837 | 1 0.04 30.96
838 | 1 0.04 30.99
839 | 1 0.04 31.03
840 | 1 0.04 31.07
841 | 1 0.04 31.10
842 | 1 0.04 31.14
843 | 1 0.04 31.17
844 | 1 0.04 31.21
845 | 1 0.04 31.25
846 | 1 0.04 31.28
847 | 1 0.04 31.32

the sum equals 100. Shouldn't the fixed effects be different for each year? Tks in advance!