Pittsfield, Illinois
Demographics
Table:
Historical population

Census	Pop.	Note	%±

1850	637	—
1870	1,621	—
1880	2,104	29.8%
1890	2,295	9.1%
1900	2,293	−0.1%
1910	2,095	−8.6%
1920	2,129	1.6%
1930	2,356	10.7%
1940	2,884	22.4%
1950	3,564	23.6%
1960	4,089	14.7%
1970	4,244	3.8%
1980	4,170	−1.7%
1990	4,231	1.5%
2000	4,211	−0.5%
2010	4,576	8.7%
2016 (est.)	4,469	[3]	−2.3%
U.S. Decennial Census[11]

Given the tabular data covering 'Pittsfield, Illinois' — "Demographics" section, formulate a single-sentence overview of the highlighted cells and provide it inside the JSON object {"answer": "YOUR ANSWER"}.