Missing Background on Chicago's Pensions

The NYT had a piece discussing the situation with Chicago's underfunded pensions. It could have used some additional context.

First it would have been useful to point out how the pensions became badly underfunded. The problem goes back to the late 1990s when Chicago, like many other state and local governments, largely stopped contributing to their pensions because they thought the run-up in the stock market made it unnecessary. They made projections, with the blessing of bond-rating agencie...