Complex sentence: In redistricting after the 1990 United States Census, the district was extended into the suburbs for the first time in 90 years, though a majority of the districts' residents (70%) lived in Chicago.
Split into simpler sentences: In redistricting after the 1990 United States Census, the district was extended into the suburbs for the first time in 90 years. A majority of the districts' residents (70%) lived in Chicago.