Sort A Table Of Data That Changes. Is Dynamic

am working on a spreadsheet that requires sorting a list of names and numbers. The numbers have a sum formula attached. I can set up the macro to sort the list fine by selecting the appropriate cells and creating the macro.

The code for this is below

Sub SurnameSort()
'
' SurnameSort Macro
' Sorts by mechanic surname
'

'
Range("A10:H13").Select
Selection.Sort Key1:=Range("B10"), Order1:=xlAscending, Header:=xlGuess _
, OrderCustom:=1, MatchCase:=False, Orientation:=xlTopToBottom, _
DataOption1:=xlSortNormal
End Sub

However, I want the macro to still be able to sort the data when I add new rows to the list later on. In other words, the code above in bold somehow needs to be modified so that "H13" extends as far down as needed.