Expanding on Jarmo's solution, you may only want the 2012 to 2022 change to be displayed in the 2022 rows
The formula for this is
If( :Year == 2022,
Col Sum( If( :Year == 2012, :Applicants total, . ), :Institution name ) /
Col Sum( If( :Year == 2022, :Applicants total, . ), :Institution name ),
.
)
Jim