year = [1986:2:1996]';
year = year - mean(year);
price= [113.5 132.2 138.7 141.5 137.6 144.2]';

A=vander(year);

c=A\price

plot(year,price,'o');

hold on; grid on;
X=linspace(min(year),max(year),400);
Y=polyval(c,X);
plot(X,Y);