Retrive the date corresponding to 70% of a dataset total count

Hi

I need to retrive the date that matches 70% of a dataset total count. In the following example I have 18 values, therefore 70% is 13 so the answer I need is 18-Apr-02. Can this be achieved whitout vba?

Thank you

Date Value
12-Jun-00 14.6
11-Aug-00 13.4
10-Oct-00 16.7
14-Feb-01 14.8
01-Oct-01 13.4
23-Oct-01 16.3
09-Nov-01 19.9
27-Nov-01 12.4
18-Dec-01 10.6
16-Jan-02 11.2
20-Feb-02 11.0
21-Mar-02 15.8
18-Apr-02 14.6
20-May-02 17.0
20-Jun-02 17.7
16-Jul-02 21.0
22-Aug-02 19.7
19-Sep-02 19.0

Dear Glenn
It is perfect,

Thank you