All unique visit for all the time

Hello to all

on first, sorry for my english… B)-

I have a one small problem with sumary of unique visitors. In this time i know how to select unique visitors by actualy month …

$url = 'index.php?module=API&method=VisitsSummary.getUniqueVisitors&idSite=3&period=month&date=today&format=PHP&prettyDisplay=true&token_auth=anonymous

$reusult= unserialize(file_get_contents($url));

it is some way to have period=ALL ??

thanks to all for answer