Dear forum users,

I have a question that I cannot seem to figure out by myself and I can't find an answer on the internet.

I want to look at the average of wind speeds over the five previous and how it affects wind turbine construction.
My data currently looks like this:

dist_code year wind_speed
3154 1995 3.7
3154 1996 3.728947
3154 1997 4.152822
3154 1998 4.138276
3154 1999 3.912632
3154 2000 3.830851
3154 2001 3.751
3154 2002 4.137689
3155 1995 2.952615
3155 1996 2.832849
3155 1997 3.146398
3155 1998 3.342508
3155 1999 3.167976
3155 2000 3.104127
3155 2001 2.838462
3155 2002 2.686159



However, I would like to have a fourth column, showing the average wind speed over the last 5 years, so something like:
dist_code year wind_speed wind_speed_prev_5yr_avg
3154 1995 3.7
3154 1996 3.728947
3154 1997 4.152822
3154 1998 4.138276
3154 1999 3.912632
3154 2000 3.830851 3.884
3154 2001 3.751 3.91
3154 2002 4.137689 3.82
3155 1995 2.952615
3155 1996 2.832849
3155 1997 3.146398
3155 1998 3.342508
3155 1999 3.167976
3155 2000 3.104127 3.084
3155 2001 2.838462 3.015
3155 2002 2.686159 2.97


Is there an easy way to do this?

Thank you very much in advance.