It might be helpful to bookmark the post office's "Price List -- Notice 123." It's their compact rate list with complete links to domestic and international mail categories. They update it for each new rate increase.

For now it is the rates effective August 28, 2016, but come the date of the rate increase, the same internet link to the old rates, jumps you automatically to the new rates.

Here is the current Notice 123 (eff. August 28, 2016), which as I say will automatically jump to the new rates on the date of the new rates -- bookmark (favorite) it:
http://pe.usps.gov/text/dmm300/Notice123.htm#1118064

Robert