add last day of month to mm/yr column

[waltnoland]

I have about 200 column of US dates that I need to insert ending days in the month for (30th/31st/28th). Unsure of how I should go about it...if,then, etc.
<TABLE style="WIDTH: 33pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=44><COLGROUP><COL style="WIDTH: 33pt; mso-width-source: userset; mso-width-alt: 1609" width=44><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; WIDTH: 33pt; HEIGHT: 12.75pt; BORDER-TOP: silver 0.5pt solid; BORDER-RIGHT: silver 0.5pt solid" class=xl64 height=17 width=44>05/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl63 height=17>04/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl64 height=17>03/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl63 height=17>02/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl64 height=17>01/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl63 height=17>12/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl64 height=17>11/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl63 height=17>10/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl64 height=17>09/10</TD></TR></TBODY></TABLE> TO <TABLE style="WIDTH: 33pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=44><COLGROUP><COL style="WIDTH: 33pt; mso-width-source: userset; mso-width-alt: 1609" width=44><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; WIDTH: 33pt; HEIGHT: 12.75pt; BORDER-TOP: silver 0.5pt solid; BORDER-RIGHT: silver 0.5pt solid" class=xl66 height=17 width=44>05/31/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl65 height=17>04/30/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl66 height=17>03/31/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl65 height=17>02/28/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl66 height=17>01/31/11</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl65 height=17>12/31/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl66 height=17>11/31/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: transparent; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl65 height=17>10/31/10</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: silver 0.5pt solid; BORDER-LEFT: silver 0.5pt solid; BACKGROUND-COLOR: #f1f5fa; HEIGHT: 12.75pt; BORDER-TOP: silver; BORDER-RIGHT: silver 0.5pt solid" class=xl66 height=17>09/30/10</TD></TR></TBODY></TABLE>

 

[barry houdini]

if you have a date in A1 you can get the end of the month with EOMONTH

=EOMONTH(A1,0)

 

[waltnoland]

As I drag down, the year remains 2011--even if I re-enter the function at the beginning of a 2010 block of dates

 

[waltnoland]

As I drag down, the year remains 2011--even if I re-enter the function at the beginning of a 2010 block of dates.

Altering the year as I drag i.e. -12, -24, -36, etc. Was hoping for a little more automation. Is there something I can nest this EOM function into?