Class FindClass
Private m_start, m_end, m_count, m_avg, m_total
Private Sub Class_Initialize()
m_count = 0
m_avg = 0
m_total = 0
End Sub

Public Function tako(pai_class_obj)
If m_start < pai_class_obj.Birthday And m_end > pai_class_obj.Birthday Then
m_count = m_count + 1
m_avg = m_avg + pai_class_obj.Age
m_total = m_total + pai_class_obj.Money
End If
End Function
End Class
'---------------
Dim ika, pai
Set ika = New FindClass
ika.StartDate("1999/1/1")
ika.EndDate("2014/1/1")
For Each col In pai_class_array
ika.tako(pai)
Next
msgbox ika.Count & "人: " & ika.Total & "円: 平均" & ika.Avg & "才"

ゲッター、セッターは自分で追加しやがれ