mktime problem

[cremesoda201]

I want to get the values for the past 11 months somehow. The problem with the code below is that it duplicates december and january for some reason. If I output all of the variables I get two "12" and two "01".

$monthback1 = date('m', mktime(0,0,0, date("n")-1, date("d"), date("Y")));
$monthback2 = date('m', mktime(0,0,0, date("n")-2, date("d"), date("Y")));
$monthback3 = date('m', mktime(0,0,0, date("n")-3, date("d"), date("Y")));
$monthback4 = date('m', mktime(0,0,0, date("n")-4, date("d"), date("Y")));
$monthback5 = date('m', mktime(0,0,0, date("n")-5, date("d"), date("Y")));
$monthback6 = date('m', mktime(0,0,0, date("n")-6, date("d"), date("Y")));
$monthback7 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));
$monthback8 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));
$monthback9 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));
$monthback10 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));
$monthback11 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));

[cremesoda201]

whoops..that was old code..

$monthback1 = date('m', mktime(0,0,0, date("n")-1, date("d"), date("Y")));
$monthback2 = date('m', mktime(0,0,0, date("n")-2, date("d"), date("Y")));
$monthback3 = date('m', mktime(0,0,0, date("n")-3, date("d"), date("Y")));
$monthback4 = date('m', mktime(0,0,0, date("n")-4, date("d"), date("Y")));
$monthback5 = date('m', mktime(0,0,0, date("n")-5, date("d"), date("Y")));
$monthback6 = date('m', mktime(0,0,0, date("n")-6, date("d"), date("Y")));
$monthback7 = date('m', mktime(0,0,0, date("n")-7, date("d"), date("Y")));
$monthback8 = date('m', mktime(0,0,0, date("n")-8, date("d"), date("Y")));
$monthback9 = date('m', mktime(0,0,0, date("n")-9, date("d"), date("Y")));
$monthback10 = date('m', mktime(0,0,0, date("n")-10, date("d"), date("Y")));
$monthback11 = date('m', mktime(0,0,0, date("n")-11, date("d"), date("Y")));

[jatar_k]

I ran that second bunch of code and it worked perfectly for me