Employee serial Number based on hiring date - vba

Question

Please assist amending the code below. what I want to do is creating unique serial number for each employee based on their hiring date eg. on was hired on 1/13/2016 the serial number comes with the last two digital number of (year,month,day+00) that means (16011300) for the one who hired in the same day and (year,month,day+01) that means (16011301)for the second one who hired in the same day. and do the same thing for those hired on different days. see pic below first what the code do but the second what I want it to be. thanks in advance for assistance
the used code:
Dim myDate As Date, i As Long, dayPart As String
Application.EnableEvents = False
For i = 2 To Rows.Count
If Cells(i, 5).Value > 1 And Not IsEmpty(Cells(i, 5).Value) Then
myDate = Cells(i, 5)
dayPart = Format(Year(myDate), "00") - 2000 & _
Format(Month(myDate), "00") & _
Format(Day(myDate), "00") & 1
Cells(i, 2) = dayPart
End If
Next i
Application.EnableEvents = True

Answer 1

If your list stays sorted by Hiring Date you can just put the following formula in B2 and draw it down:
=IF(E2=E1,B1+1,VALUE(TEXT(E2,"YYMMDD")&"00"))
EDIT:
In case of unsorted lists use the following formula in B2 and draw it down:
=TEXT(E2,"YYMMDD")&TEXT(COUNTIF($E$1:E1,E2),"00")
or (if you want it as a number instead of text):
=VALUE(TEXT(E2,"YYMMDD")&TEXT(COUNTIF($E$1:E1,E2),"00"))

Answer 2

You cannot apply a format mask (see Number Format Codes) that included both date/time characters as well as a regular integer character, but if you convert the integer to the number of hours then your Emp no can be created in one shot.
Dim i As Long, seq As Long, dayPart As String
With Worksheets("employees")
For i = 2 To .Cells(Rows.Count, "E").End(xlUp).Row
seq = Application.CountIf(.Columns(5).Resize(i - 1, 1), .Cells(i, "E").Value)
dayPart = Format(.Cells(i, "E").Value2 + TimeSerial(seq, 0, 0), _
"yymmddhh")
.Cells(i, "B") = dayPart
Next i
End With
After collecting the number of previous matching dates with a COUNTIF function, the returned integer is converted to hours with TimeSerial and added to the hiring date. A format mask of yymmddhh generated the entire Emp no.
Granted, this is limited to 24 new employee hires per day.