Determining Adherence for building based on patient level data

Here is an example of the data set.  There is obviously so much more, but these are the key pieces.

Site:                       Resident:           Metric:                  Intitial Score      End  Score

Bldg A                    1                         Gait Speed             1                          2

Bldg A                    2                         Gait Speed             2                          2

Bldg A                    3                         Gait Speed             1                          1

Bldg B                    4                         Grip Strength         2                          2

Bldg B                    5                         Grip Strength         2                          2

Bldg B                    6                         Grip Strength         2                          2

Rolled up data:

Site:                        Metric               Adherence

Bldg A                     Gait Speed          80%

Bldg B                     Gait Speed          60% 

The data is at a patient/ resident level, but I am rolling it up to a site level using the measure I put in my original post.  The 2's and 1's represent a yes or no depending on whether the metric was performed on each resident.  Based on my site rollup measure, I need to then determine of those buildings, how many scored 80% compared to all sites.  This represents the % of adherent sites.  If the data was all at a site level, it would be easy, I would add a column with an if statement and then use a count of adherent sites divided by all sites.  The patient level data is confusing me...