Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
List of whips in the Australian House of Representatives
Table title:
Liberal Party of Australia
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Whip </th><th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Deputy Whip </th><th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Leader </th></tr>
<tr> <td colspan=1 rowspan=1 > Allan Guy (Wilmot) </td><td colspan=1 rowspan=1 > 21 February 1945 </td><td colspan=2 rowspan=3 >  </td><td colspan=1 rowspan=10 > Robert Menzies </td></tr>
<tr> <td colspan=1 rowspan=1 > Allan McDonald (Corangamite) </td><td colspan=1 rowspan=1 > 8 November 1946 </td></tr>
<tr> <td colspan=1 rowspan=3 > Jo Gullett (Henty) </td><td colspan=1 rowspan=3 > 16 February 1950 </td></tr>
<tr> <td colspan=1 rowspan=1 > Reginald Swartz (Darling Downs) </td><td colspan=1 rowspan=1 > c. Sept 1950 </td></tr>
<tr> <td colspan=1 rowspan=1 > Hubert Opperman (Corio) </td><td colspan=1 rowspan=1 > 20 August 1952 </td></tr>
<tr> <td colspan=1 rowspan=1 > Hubert Opperman (Corio) </td><td colspan=1 rowspan=1 > 15 December 1955 </td><td colspan=1 rowspan=1 > Henry Pearce (Capricornia) </td><td colspan=1 rowspan=1 > Unknown </td></tr>
<tr> <td colspan=1 rowspan=1 > Henry Pearce (Capricornia) </td><td colspan=1 rowspan=1 > 5 February 1960 </td><td colspan=1 rowspan=1 > William Aston (Phillip) </td><td colspan=1 rowspan=1 > 10 March 1960 </td></tr>
<tr> <td colspan=1 rowspan=1 > Fred Chaney, Sr. (Perth) </td><td colspan=1 rowspan=1 > 23 January 1962 </td><td colspan=1 rowspan=1 > Peter Howson (Fawkner) </td><td colspan=1 rowspan=1 > 23 February 1962 </td></tr>
<tr> <td colspan=1 rowspan=1 > Peter Howson (Fawkner) </td><td colspan=1 rowspan=1 > 22 December 1963 </td><td colspan=1 rowspan=1 > William Aston (Phillip) </td><td colspan=1 rowspan=1 > 22 December 1963 </td></tr>
<tr> <td colspan=1 rowspan=2 > William Aston (Phillip) </td><td colspan=1 rowspan=2 > 10 June 1964 </td><td colspan=1 rowspan=2 > Bert Kelly (Wakefield) </td><td colspan=1 rowspan=2 > c. August 1964 </td></tr>
<tr> <td colspan=1 rowspan=3 > Harold Holt </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=3 > Dudley Erwin (Ballarat) </td><td class="highlighted"  colspan=1 rowspan=3 > 21 February 1967 </td><td colspan=1 rowspan=1 > James Killen (Moreton) </td><td colspan=1 rowspan=1 > 21 February 1967 </td></tr>
<tr> <td colspan=1 rowspan=3 > Kevin Cairns (Lilley) </td><td colspan=1 rowspan=3 > 23 August 1967 </td></tr>
<tr> <td colspan=1 rowspan=3 > John Gorton </td></tr>
<tr> <td colspan=1 rowspan=4 > Max Fox (Henty) </td><td class="highlighted"  colspan=1 rowspan=4 > 12 February 1969 </td></tr>
<tr> <td colspan=1 rowspan=3 > Geoffrey Giles (Angas) </td><td colspan=1 rowspan=3 > 24 November 1969 </td></tr>
<tr> <td colspan=1 rowspan=1 > William McMahon </td></tr>
<tr> <td colspan=1 rowspan=2 > Billy Snedden </td></tr>
<tr> <td colspan=1 rowspan=2 > Victor Garland (Curtin) </td><td colspan=1 rowspan=2 > 14 June 1974 </td><td colspan=1 rowspan=3 > Don Cameron (Griffith) </td><td colspan=1 rowspan=3 > 14 June 1974 </td></tr>
<tr> <td colspan=1 rowspan=4 > Malcolm Fraser </td></tr>
<tr> <td colspan=1 rowspan=3 > John Bourchier (Bendigo) </td><td colspan=1 rowspan=3 > 26 March 1975 </td></tr>
<tr> <td colspan=1 rowspan=1 > John Hodges (Petrie) </td><td colspan=1 rowspan=1 > 16 March 1978 </td></tr>
<tr> <td colspan=1 rowspan=1 > Ross McLean (Perth) </td><td colspan=1 rowspan=1 > May 1982 </td></tr>
<tr> <td colspan=1 rowspan=1 > Don Dobie (Cook) </td><td colspan=1 rowspan=1 > 16 March 1983 </td><td colspan=1 rowspan=1 > Ewen Cameron (Indi) </td><td colspan=1 rowspan=1 > 16 March 1983 </td><td colspan=1 rowspan=1 > Andrew Peacock </td></tr>
<tr> <td colspan=1 rowspan=1 > Ewen Cameron (Indi) </td><td colspan=1 rowspan=1 > 9 September 1985 </td><td colspan=1 rowspan=1 > Neil Andrew (Wakefield) </td><td colspan=1 rowspan=1 > 9 September 1985 </td><td colspan=1 rowspan=1 > John Howard </td></tr>
<tr> <td colspan=1 rowspan=1 > Michael MacKellar (Warringah) </td><td colspan=1 rowspan=1 > 12 May 1989 </td><td colspan=1 rowspan=1 > David Hawker (Wannon) </td><td colspan=1 rowspan=1 > 12 May 1989 </td><td colspan=1 rowspan=1 > Andrew Peacock </td></tr>
<tr> <td colspan=1 rowspan=1 > Bob Halverson (Casey) </td><td colspan=1 rowspan=1 > 11 April 1990 </td><td colspan=1 rowspan=1 > Neil Andrew (Wakefield) </td><td colspan=1 rowspan=1 > 11 April 1990 </td><td colspan=1 rowspan=2 > John Hewson </td></tr>
<tr> <td colspan=1 rowspan=1 > Rod Atkinson (Isaacs) </td><td colspan=1 rowspan=1 > 7 April 1993 </td><td colspan=1 rowspan=1 > Paul Filing (Moore) </td><td colspan=1 rowspan=1 > 7 April 1993 </td></tr>
</table>
Question:
When was Dudley Erwin a Government Whip?
Answer:
Dudley Erwin was a Government Whip from 1967 to 1969.