Column B    Column C
11  21 Oct      0.87%
12  22 Oct      1.38%
13  23 Oct      0.04%
14  24 Oct      0%
15  25 Oct      0%

{=AVERAGE( IF(B5:B373 < TODAY(); C5:C373))}

Column B    Column C
11  21 Oct      0.87%  < literal value
12  22 Oct      1.38%  < literal value
13  23 Oct      0.04%  < literal value
14  24 Oct      0.76%  < =C2
15  25 Oct      0,76%  < =C2