Detroit bankruptcy was years in the making

AP

Kevyn Orr

The long decline of Detroit, a hollowed-out relic that once was hub for the U.S. automotive industry, led on Thursday to the biggest U.S. municipal bankruptcy filing in the country's history.

(Read More: Detroit becomes largest US city to file for bankruptcy)

Here are some facts Kevyn Orr, the emergency manager who has been running Detroit since March, and Governor Rick Snyder cited for leading to the city's bankruptcy filing:

Detroit, which saw its population drop from 1.8 million in 1950 to less than 700,000 by 2012, is drowning under more than $18 billion in debt.

(Read More: Detroit prepares for bankruptcy as soon as Friday)

City tax rates are at legal limits and expenditures have exceeded revenue for six years. Property taxes were delinquent on 47 percent of the city's taxable properties in 2011.

The accumulated budget deficit, which totaled $326.6 million at the end of fiscal 2012, is projected to climb to more than $1.3 billion by fiscal 2017 absent structural changes.

Detroit has long relied on borrowing and deferred payments to its pension funds to keep afloat.

(Read More: Detroit emergency manager: We had to draw a line somewhere)

The city's unemployment rate, which stood at 18.3 percent in June 2012, has nearly tripled since 2000.

The murder rate is at its highest level in nearly 40 years and it takes police an average of nearly an hour to respond to calls. The national average is 11 minutes.

(Read More: Detroit reaches 'important settlement' with some creditors)

In the first quarter of 2013, only a third of the city's ambulances were working and about 40 percent of Detroit's street lights were not working.

Negotiated settlements on city debt are not possible outside of bankruptcy "given the vast and fragmented pool of potential creditors," Orr's letter stated. That pool includes city retirees, labor unions, bondholders and bond insurers.