Just talk to your PM or realtor to dig the data up if you do not know it.

I do not do a lot of volume, so it would take me a long time to get a good data set just based on those numbers. 

One of them told me they only have to provide 15 days notice, which doesn’t help if I am on vacation for a few weeks or haven’t checked my PO Box in a few weeks.

You might check with a local attorney on this.In NY where I am, the period is 10 years.

I need to source the data myself, run the numbers, check the calculations, eventually build my own custom spreadsheet etc. 

If you want to understand 5-year outlook, I'd look for multifamily construction data in your area to understand what level of new units is and will be coming online in the near future. 

Finally, the data they are using to demonstrate the price hike is WAY out-dated.

Be sure to check and see if there’s any tax benefits to you from buying from the non-profit.

@Lindsay Davis - I appreciate the data and the dialogue.  

That being said, its probably still worth looking at the data at those prices