I've been looking at the USA figures a bit more. There were 28,915 baptisms, but the actual no only increased by 13,210. This leaves 15,715 unaccounted for. A death rate of 8.25 per 1000 would account for 8,209 of these, but that still leaves 7,496 people who ceased to be counted as baptised jw's.
An average of 995,071 publishers with a birthrate of 14.14 per 1000 could expect to increase by 14,070 per year, not taking into account the death rate. Of the 28,915 baptisms, this would account for nearly half of them.
http://en.wikipedia.org/wiki/List_of_countries_by_birth_rate
http://en.wikipedia.org/wiki/List_of_countries_by_death_rate