Unfortunately energy use specs are not really attainable unless the manufacturer is contacted. Even then, pulling old specs would probably not be on their agenda. I can tell you a few things however to help make your decision.
Comparing wattage and amps between a 15 year old unit and new.
Compressor uses 3/4 to 1 amp to run now, then 2-3 amps.
Compressor now runs more, however is maintaining temps more easily due to extremely accurate sensors. Then, run based on a capillary type thermostat.
Adaptive defrost systems only allow defrost to occur when required, then defrost timers went into defrost every 8-10 hours, needed or not.
A lot of newer units use variable speed DC fan motors, then all 120 volt AC single speed.
Harbor freight sells a product called "Kill-o-watt". You plug it into a wall, then your appliance into it. It'll tell you everything in terms of power consumption. The reality though, is finding the information you desire would require the manufacturers engineers digging through piles of old info. Please remember, Amana was purchased by Maytag in the early 2000s, then Maytag was purchased by Whirlpool in 2006. A lot of stuff like this is just unattainable anymore. I can promise you, anything you buy nowadays will be 2 to 3 times more efficient than a product bought 14 years ago. You can call Amana(NNN) NNN-NNNNto see if they can locate a manual for you. I just tried, and the search brought up 0 results.