private int daysInYear(int year) {
		Duration d = new Duration(new DateTime(year, 1, 1, 0, 0), new DateTime(year + 1, 1, 1, 0, 0));
		return (int)d.getStandardDays();
	}
A counter that tracks integral values but also remembers how its value was distributed over time.

<p>
This core class only holds data structures. Depending on backing stores, logic for computing totals may be
implemented in a specialization of this class or at the repository level.
</p>

@author Luke Taylor
@author Eric Bottard
spring-xd-analytics/src/main/java/org/springframework/xd/analytics/metrics/memory/InMemoryAggregateCounter.java