Table:
undergraduate degree
graduate degree

unadjusted gap
adjusted gap
unadjusted gap
adjusted gap

model a
model b
model a
model b

percent

cohort

2006
-1.9
-1.8
-0.6
-5.8
-3.7
1.7

2007
-0.5
0.6
0.7
-15.8
-13.1
-8.2

2008
..
..
..
..
..
..

2009
-7.6
-7.3
-7.8
-9.8
-8.1
-9.4

2010
-7.7
-7.2
-10.0
-13.6
-9.8
-8.4

2011
-10.1
-8.5
-11.1
-3.2
2.1
0.5

Reconstruct the table in the presented picture as an HTML-style table in text.

<table border="1" cellspacing="0">
<tr> <td rowspan="4">  </td> <td colspan="3"> undergraduate degree </td> <td colspan="3"> graduate degree </td> </tr>
<tr> <td rowspan="2"> unadjusted gap </td> <td colspan="2"> adjusted gap </td> <td rowspan="2"> unadjusted gap </td> <td colspan="2"> adjusted gap </td> </tr>
<tr> <td> model a </td> <td> model b </td> <td> model a </td> <td> model b </td> </tr>
<tr> <td colspan="6"> percent </td> </tr>
<tr> <td> cohort </td> <td colspan="6">  </td> </tr>
<tr> <td> 2006 </td> <td> -1.9 </td> <td> -1.8 </td> <td> -0.6 </td> <td> -5.8 </td> <td> -3.7 </td> <td> 1.7 </td> </tr>
<tr> <td> 2007 </td> <td> -0.5 </td> <td> 0.6 </td> <td> 0.7 </td> <td> -15.8 </td> <td> -13.1 </td> <td> -8.2 </td> </tr>
<tr> <td> 2008 </td> <td> .. </td> <td> .. </td> <td> .. </td> <td> .. </td> <td> .. </td> <td> .. </td> </tr>
<tr> <td> 2009 </td> <td> -7.6 </td> <td> -7.3 </td> <td> -7.8 </td> <td> -9.8 </td> <td> -8.1 </td> <td> -9.4 </td> </tr>
<tr> <td> 2010 </td> <td> -7.7 </td> <td> -7.2 </td> <td> -10.0 </td> <td> -13.6 </td> <td> -9.8 </td> <td> -8.4 </td> </tr>
<tr> <td> 2011 </td> <td> -10.1 </td> <td> -8.5 </td> <td> -11.1 </td> <td> -3.2 </td> <td> 2.1 </td> <td> 0.5 </td> </tr>
</table>