Getting Average Percentage in a Certain Date Range from Another Sheet

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Hello everyone, I got some problem and I need your kindly help

Here's my problem:
In my workbook, I got 2 sheets. The first one contains the dates, stocks, sold items, and the percentage (the Type column doesn't matter right now).

And the second one contains the date range and the average percentage. And I don't know the formula to get the average percentage (Sheet 2, D6-D11) from the Sheet 1 (F5-F19) in a certain date range in Sheet 2 (B6-C6 --- B11-C11)


By the way, here's the attachment
Book1.xls

Thank you for your time to read this and kindly help.

Regards,