Having a style= and a class= seems odd to me but here's what I tried just now which worked but which you may find odd. To be honest any style= on a tag is a bad smell for me.
In the css for the table, set its width to 100%;
Code:
table {
width: 100%;
}
Then make classes for the different widths;
Code:
.tablebig {
width: 80%;
}
.tablesmall {
width: 40%;
}
Then put the table inside a div with either of those classes;
Code:
<div class="tablesmall">
<table>
...
I have no idea how portable that is.