In the third filter, pddistrict, notice that the value for
PARK is missing; there are only 9 policing districts available in the
filter.
This is the result of filtering based on category BAD CHECK and date
range 2010-01-01 through 2010-12-31. The resulting
subset of data in the dataset does not include rows where pddistrict
equals PARK.
If you select another date range, such as years 2008 through 2014, all 10 districts
show up on the pddistrict filter.