function y = fill46_51(a,x)
%FILL46_51    Take annual values for 1946-1951 in vector a and the
%             first quarter of 1952 in x and interpolate to get 
%             data for 1946:1-1952:1 in y.

x1   = x;
y    = zeros(4,6);
for i=6:-1:1;
  d      = (x-a(i))*.4;
  x0     = a(i)-1.5*d;
  y(:,i) = linspace(x0,x-d,4)';
  x      = x0;
end;
y    = [y(:);x1]   

