function ts=hist_returns(asset, start_date, end_date)

% Set Defaults
if nargin==0
  start_date=datestr(datenum(date)-365,'ddmmyyyy');
  end_date=datestr(date,'ddmmyyyy');
  asset='LAZ';
elseif nargin==1
  start_date=datestr(datenum(date)-365,'ddmmyyyy');
  end_date=datestr(date,'ddmmyyyy');    
end

stocks = hist_stock_data(start_date, end_date, asset);

r1=stocks.Date(1:size(stocks.Date,1)-1);
r2=(stocks.Close(1:size(stocks.Close,1)-1)./stocks.Close(2:size(stocks.Close,1)))-1;

ts=[datenum(r1) r2];
end