The average PERA payment to individuals is $2893 not the $3750 you use in your example.   PERA put out a benefit chart that showed payout amounts by recipients that showed the vast majority fell into the 10-50k a year range.   

This document also showed the average payout of retirees at 60 was 14 years service and an annual payment of $11784 per year.   Some of those positions as in federal service force retirement at a certain age.   For what it's worth the average age of retirement in PERA in 2015 was 61.5 and had a 20.63 years of service and a monthly payment of $2586.  From the charts then that average individual was getting a payment of 52% of their HAS of around 60000 a year.   That is their three highest paying years only averaged 60,000 (including all the alleged spiking).  The highest paying years of experience is barely over the average income earned in the state of 56,000.