I have a Datalogger that recorded data each half an hour for the past year and the data is stored like the

12.00 12.30 13.00 ......
17.7.12 | value1 | value2 | value3
18.7.12 | value4 | value5 | value6

My question is now how I can plot the data in chronological order including all values, from value 1 to value 6?
At the moment I am determining the average of each row and just plotting one datapoint per day. But I would like to plot all the data. Reason is that it is an electrical load profile of a city and that varys throughout the day

Ideally I would like to use a Pivot Chart for it.
Thank you