Date Open
22/08/08 11426.79
21/08/08 11415.23
20/08/08 11345.94
19/08/08 11478.09
18/08/08 11659.65
15/08/08 11611.21
14/08/08 11532.07
13/08/08 11632.81
12/08/08 11781.7
11/08/08 11729.67
08/08/08 11432.09
07/08/08 11655.42
06/08/08 11603.64
05/08/08 11286.02
04/08/08 11326.32
01/08/08 11379.89
31/07/08 11577.99
30/07/08 11397.56
29/07/08 11133.44

I just want to make an easy lookup which gives me the open value on a specific date, however excel keeps on giving me the last value in my choosen array.
=LOOKUP(a5,a2:a20,b2:b20)
I just choose a date out of the date array, but even that doesn't work.
Any ideas? I think excel got problems coping with the dates, what can I do ?!?