Using the information below, determine the minimum-variance portfolio that yields an expected return of at least 0.22

Historical data	% return on	Closing stock prices
Year	the Market	Ford	Lilly	Kellogg	Merck	HP
1983		14.13	14.47	8.09	5.02	42.38
1984	0.06	15.21	16.5	10	5.22	33.88
1985	0.32	19.33	27.88	17.38	7.61	36.75
1986	0.18	28.13	37.13	25.88	13.76	41.88
1987	0.05	37.69	39	26.19	17.61	58.25
1988	0.17	50.5	42.75	32.13	19.25	47.25
1989	0.31	43.63	68.5	33.81	25.83	31.88
1990	-0.03	26.63	73.25	37.94	29.96	57
1991	0.31	28.13	83.5	65.38	55.5	69.88