Emphasis. The colon can be used to emphasize a phrase or single word at the end of a sentence. An em dash can be used for the same purpose. In the second example below, an em dash is more common than a colon, though the use of a colon is nevertheless correct.
Lawrenceville, GA Income and Careers. As of 2010-2014, the per capita income of Lawrenceville is $19,178, which is lower than the state average of $25,427 and is lower than the national average of $28,555. Lawrenceville median household income is $42,459, which has shrunk by 1.94% since 2000.
The median household income ($65,376) for 30043 is less than the median household income for 30519 ($71,693), 30097 ($96,390), 30019 ($84,446), and 30024 ($101,390). But it's more than 30044 ($51,974), 30046 ($43,610), 30096 ($50,167), Lawrenceville ($41,743), and Gwinnett County ($60,289).