wp_get_archives
already have post_type="post"
by default and to replace it try this:
add_filter('getarchives_where','my_archives_filter');
function my_archives_filter($where_clause) {
str_replace( "post_type="post"" , "post_type="page"" , $where );
}
in sidebar:
add_filter('getarchives_where','my_archives_filter');
wp_get_archives('type=yearly');
remove_filter ('getarchives_where','my_archives_filter');