previous 2 years average and show the data

Hi All,

Need help in solving the below . Need to calculate the average of previous year month .

Eg:

Date                           Regular Time
1/1/2017 0:00            55352.36
2/1/2017 0:00            48446.67
3/1/2017 0:00            59533.84
4/1/2017 0:00            47379.48
5/1/2017 0:00           59671.17
6/1/2017 0:00            53114.08
7/1/2017 0:00           45445.73
8/1/2017 0:00          52435.5
9/1/2017 0:00          49263.75
10/1/2017 0:00        56204.57
11/1/2017 0:00        55539.25
12/1/2017 0:00       40924.8
1/1/2018 0:00         53356.25
2/1/2018 0:00         41935.08
3/1/2018 0:00       51504.59
4/1/2018 0:00       50411.89
5/1/2018 0:00      56962
6/1/2018 0:00     49064.76
7/1/2018 0:00      46813
8/1/2018 0:00      48939.38
9/1/2018 0:00      46932.33
10/1/2018 0:00      30365.25
11/1/2018 0:00    2000
12/1/2018 0:00    112

Output will be (jan 2016+Jan2017)/2.

Here is the outlput.

Month   Regular time
Jan    54354.305
Feb   45190.875
Mar   55519.215
Apr   48895.685
May   58316.585
Jun   51089.42
Jul   46129.365
Aug   50687.44
Sep   48098.04
Oct   43284.91
Nov    28769.625
dec   20518.4