Scenario this

Oregon’s Public Employees Retirement System has at least $24.5 billion in unfunded liability.

Which comes to 15% of GDP.  What is the likelihood that a third of the employees might opt for early retirement.  What is the average age?

The median age in 2010 was 38.4 (13.9% of pop. was 65 years old or older).

OK, so maybe 20% of the employees might have a five year flexibility on selecting retirement.   It is possible that some 20% of that 15% could become due over a two year period.  This happens as regulations and taxes change because the governor in Oregon is looking to tax just about everything.

The most likely outcome is a short two year period with GDP dropping  by 1.5% per year, putting Oregon at zero growth.  This can happen if everyone freaks about the taxes and legislation turns into a mess or the governor goes full secret and surprises us.  Some small glitch will certainly cause a pension stampede.