Set priority of a plugin through code

how to set the priority of a plugin by default, so that after installation and activation it is at the bottom of plugin list automatically.
I know that we can set the priority in the administration section but how can we set that in code so that when this plugin is installed on another site, by defult it is at the bottom of plugin list.

ihave tried:
elgg_register_event_handler('init', 'system', 'myplugin_init', 999999);
but it does'nt seem to work. please help.
Thanks in advance
Im using elgg 1.8.16