According to the documentation:
$.cookie('the_cookie', 'the_value', { expires: 7 });
expire
define lifetime of the cookie. Value can be a Number which will be interpreted as days from time of creation or a Date object. If omitted, the cookie becomes a session cookie.
So for your case:
$.cookie('_usci', numValue.toString(), { expires: 5 * 365 });
This will make your cookie expire in five years from now.