Closing Market Price and NAV History

Date	Market Price1	Net Asset Value2	Bid/Ask Midpoint	Volume1	Net Assets2
3/29/2018	$120.50	$120.55	$120.51	508,552	$6,992,016,028
3/28/2018	$117.78	$117.81	$117.80	4,226,413	$6,827,306,907
3/27/2018	$119.60	$119.65	$119.62	654,360	$6,736,062,797
3/26/2018	$124.42	$124.43	$124.42	580,698	$7,005,354,855
3/23/2018	$120.80	$120.83	$120.82	647,206	$6,808,555,691
3/22/2018	$124.03	$124.04	$124.02	585,505	$6,977,173,261
3/21/2018	$127.37	$127.36	$127.39	360,443	$7,144,779,469
3/20/2018	$127.16	$127.16	$127.17	337,185	$7,127,569,997
3/19/2018	$126.91	$126.90	$126.91	645,056	$7,112,676,690
3/16/2018	$129.87	$129.96	$129.93	242,229	$7,278,033,675
3/15/2018	$130.38	$130.40	$130.39	446,229	$7,693,640,659
3/14/2018	$130.90	$130.89	$130.93	488,368	$7,323,558,141
3/13/2018	$129.20	$129.18	$129.18	562,694	$7,227,798,309
3/12/2018	$131.25	$131.23	$131.26	637,543	$7,309,246,698
3/9/2018	$131.02	$131.07	$131.05	616,276	$7,267,896,373
3/8/2018	$128.89	$128.91	$128.90	409,685	$7,122,241,035
3/7/2018	$128.56	$128.52	$128.54	471,126	$7,100,748,274
3/6/2018	$127.00	$126.97	$126.98	5,604,493	$7,002,268,381
3/5/2018	$126.04	$125.99	$126.02	535,692	$6,482,148,098
3/2/2018	$123.80	$123.81	$123.80	523,799	$6,345,089,367
3/1/2018	$121.70	$121.75	$121.74	646,382	$6,221,212,714