Monopoly or Duopoly, Private or Public Ownership?

Yesterday when I got home there was a nice letter in the mail from my electricity provider AGL and it starts as follows.

“ We’d like to thank you for being an AGL customer”

It then proceeds to inform me that due to costs reviews and several other factors the price of electricity is going up. It provides the changes on the reverse of the letter but fails to tell me how much my electricity has risen in percentage terms.

Well I calculated it and the result is this. Domestic supply has been increased by 15.67%. Off Peak has been increased by 15.63%.

In addition many service providers have withdrawn from the market in QLD claiming they cannot make money from selling electricity in this state making the retail service a virtual duopoly. What I would like to know is how much of the increase is true costs and how much is to bolster profits.