fid = fopen('census.dat','r');
Npb = fscanf(fid,'%g');
status = fclose(fid);
[N p]=size(Npb);
Np(1:N)=Npb(N:-1:1);
% x=Np(1:N-1);
% y=Np(2:N);
% a=sum(x.*y)/sum(x.^2)
% plot(x,y,'.')
% hold on
% plot(x,a*x,'b')
% hold off
