Simplify the following text for a Grade 3 native English-speaking person.
Original: Its population was 1,430 in 1801 , 4,049 in 1901 , 79,724 in 2001 and 84,651 in 2007 .
Simplified: In 1801 , 1,430 people lived in Stevenage . In 1901 , 4,049 people lived in Stevenage .