private static String i(final IntMomentStatistics statistics) {
		final NumberFormat nf = NumberFormat.getIntegerInstance();
		return format(
			"sum=%s; mean=%6.9f",
			nf.format(statistics.sum()), statistics.mean()
		);
	}
Return the minimal and maximal fitness.

@return minimal and maximal fitness
jenetics/src/main/java/io/jenetics/engine/EvolutionStatistics.java