I used the same rates as the department is using. It's the one in 10 claim rate, 10% claim rate, for sickness. For maternity and parental benefits, it's essentially everyone who joins, and the department assumes 20,000 people joining per year and 20,000 claiming. Essentially they're saying whoever joins will draw benefits, which seems reasonable under this particular scheme for maternity and parental benefits.
On December 10th, 2009. See this statement in context.