Macro Experts Please Help A Destitute Man!

I need a macro that does two things.

1.) it adds month day year to the hours starting with 1/22/05 and once it reaches 0:00 on 1/23/05 it goes on through all the hours for that day and continues on to the end of the spreadsheet.

2.) I then need a macro that will find the mean (average) for all the similar hours in a month. for ex. I need to average all the 11:00's in January, all 12:00's in January and so on.

is this possible? please help?

for information purposes, the percentage of capacity by hour column is column G on my spread sheet, Hour column is Column H and the MDY column is I
Percentage of Capacity By Hour Hour
0.00% 11:00 1/22/2005
0.00% 12:00
0.00% 13:00
0.00% 14:00
0.00% 15:00
0.00% 16:00
0.00% 17:00
0.00% 18:00
0.00% 19:00
0.00% 20:00
0.76% 21:00
1.59% 22:00
1.38% 23:00