average (';' LIST )*

static String	_average	= "${average;<list>[;<list>...]}";

public String _average(String args[]) throws Exception {
	verifyCommand(args, _sum, null, 2, Integer.MAX_VALUE);

	List<String> list = toList(args, 1, args.length);
	if (list.isEmpty())
		throw new IllegalArgumentException("No members in list to calculate average");

	double d = 0;

	for (String s : list) {
		double v = Double.parseDouble(s);
		d += v;
	}
	return toString(d / list.size());
}