When a city experiences a sharp decline in population, the city' s tax revenues, which pay for such city services as police protection and maintenance of water lines, also decrease. The area to be policed and the number and length of the water lines to be maintained, however, do not decrease. Attempting to make up the tax revenue lost by raising tax rates is not feasible, since higher tax rates would cause even more residents to leave.
The information given most strongly supports the general claim that if a city's tax rates are held stable over a period of time, neither the population nor the levels of city services provided will tend to decline over that period.