[Jetpack] Get the number of subscribers on your site

plugin.php

<?php

// Get the number of subscribers on your site
function jeherve_sub_count() {
	if ( class_exists( 'Jetpack_Subscriptions_Widget' ) ) {
		$subcount = Jetpack_Subscriptions_Widget::fetch_subscriber_count();

		echo $subcount['value'];
	}
}