display aggregation info

[mrcnc]

As a citizen, I would like to view interesting aggregations on the 311 data.

Number of issues per request type
Most recently open issue
Most recently closed issue
Percentages of time spent open (median & histogram)

[mrcnc]

Here's an example of an "issue per request type" infographic:
https://infogram.com/80666795-50f7-4496-ae96-7b7dabe510d9