Percentage in Excel is a number, as all other numbers, so how are you
going to distinguish between 1 and 100%? unless there is no
possibility to have a value of 100% in a cell, and if you can use an
Auxiliary column, you can say in an Aux column(say B4):
=IF(B3<1=FALSE,B3,"") and copy it through under your data, and in the
end, =sum(B3:Bx)

This will cause problems if you have decimal values in your cells like
0.5 because it will ignore them and the second condition is not to
have a 100% because it will be treated as 1.
My solution is very primitive, and i know that the other persons who
are more experienced will come with many better solutions, it is just
that i wanted to help.

Regards