Simplify the following text for a Grade 9 native English-speaking person.
Original: After the unification the city 's population declined from over 100,000 in 1989 to roughly 75,000 in 2005 through emigration .
Simplified: After the fall of the Berlin Wall the population dropped from over 100,000 in 1989 down to roughly 75,000 in 2005 through emigration .