Here is a link to some background definition on the AAO, ( Antartic Oscillation )
Also included from this link is some tabulated data of AAO index from 1948 to 2011
http://research.jisao.washington.edu/data/aao/slp/
I was looking for the record lowest AAO. But l have come to realize there are various ways of computing the AAO,and so l am not confident of making a valid comparison
However, it is evident that the AAO has been steadily trending positive since the data began in 1948 and is clearly evident from the time series below.
What is also interesting is that the trend is linear . The trend runs parallel to Southern Hemisphere surface warming during this same period.
Source