Vista - # of DropBox Elements to be Displayed

<Select NAME="MyDropList" SIZE = "1">
<%For N = 0 to 28%>
<%If Request("PgClass") = "" then%>
<Option Value="<%=UVDescs(N)%>"><%=UVDescs(N)%></Option>
<%Else%>
<%If Request("PgClass") = UVDescs(N) then%>
<Option Selected="<%=UVDescs(N)%>"><%=UVDescs(N)%>
<%Else%>
<Option Value="<%=UVDescs(N)%>"><%=UVDescs(N)%>
</Option>
<%End If%>
<%End If%>
<%Next%>
</Select>

The above code currently displays only the first (9) nine elements, I would
like for it to display about 15 or 17.

Why is it displaying only 9?

Thank You in Advance

Granny Leona