<option value="all" selected="selected"><?php _e('All Content'); ?></option>
<?php foreach ( get_post_types( array( 'public' => true, 'can_export' => true ), 'objects' ) as $post_type_obj ) { ?>
<option value="<?php echo $post_type_obj->name; ?>"><?php echo $post_type_obj->labels->name; ?></option>
<option value="all" selected="selected"><?php _e('All Content'); ?></option>
<?php foreach ( get_post_types( array( 'public' => true, 'can_export' => true ), 'objects' ) as $post_type_obj ) { ?>
<option value="<?php echo $post_type_obj->name; ?>"><?php echo $post_type_obj->labels->name; ?></option>