[UPDATE / CLARIFICATION], if you click on http://www.sbs.gob.pe/app/stats/tipodecambiocontablexls.asp?fec=18/08/2016, it will generate an excel file with the data as of 18/08/2016. I tried to use the matlab function webread without success:
url = 'http://www.sbs.gob.pe/app/stats/tipodecambiocontablexls.asp?fec=06/05/2016'; options = weboptions('ContentType','text','ArrayFormat','csv'); x=webread(url,options);