| Essex - Population Change | FIPS Code=07030 |
| Absolute Population Change, 1970-1980 | 3441 |
| Per Cent Population Change, 1970-1980 | 31.42 |
| Absolute Population Change, 1980-1990 | 2106 |
| Per Cent Population Change, 1980-1990 | 14.63 |
| Population Estimate, 1996 | 18044 |
| Population Estimate, 2000 | 18889 |
| Population Estimate, 2005 | 19915 |
| Population Estimate, 2010 | 20533 |
| Population Estimate, 2015 | 21225 |
| Absolute Population Change, 1990-1996 | 1546 |
| Per Cent Population Change, 1990-1996 | 9.37 |
| Absolute Population Change, 1996-2005 | 1871 |
| Per Cent Population Change, 1996-2005 | 10.37 |
| Absolute Population Change, 2005-2015 | 1310 |
| Per Cent Population Change, 2005-2015 | 6.58 |