The more the sector's workforce and income grow, the more important it is to have better and more frequent data - even if it is not comprehensive enough to describe the sector in all its manifestations.
Perhaps the most striking thing to be confirmed by this year's alamanac is the increasing dominance of a small number of super-charities. The biggest 18 organisations now draw in an eighth of the sector's income.This is what Iain Duncan Smith, the former Conservative leader, has called the Tescoisation of the voluntary sector.
There is nothing inherently wrong with large charities. Size and critical mass can be the key to effectiveness, and if there are too many smaller charities working in the same area, duplication and inefficiency can often outweigh any benefits of competition. But the larger and more dominant charities become, the more they must be able to show that they meet certain important criteria. One of these is independence, especially in the case of charities that receive a high proportion of their income from the state. Another is effectiveness. The more dominant a charity becomes, the better it should be able to show in a clear and transparent manner that it is achieving its declared objectives.
But even if they fulfil those criteria, how good are the big charities at innovation? There is always the supertanker syndrome - size can reduce nimbleness and flexibility. It is often the smaller charities that have the new ideas while the larger ones become set in their ways, the victims of their own success. If the big boys are hoovering up all the funds, life can become much harder for those who have less to lose and are able to think more widely and come up with innovative ideas.
And what about community action? The alamanac shows that the income share of the smallest charities is declining most quickly, and no doubt one factor in this is that local authorities are cutting back grants in favour of contracts for the delivery of services. Community groups will be stronger and more independent if they are financed by voluntary donations, but the reality - especially in more deprived areas - is that they need public funds. And they are more likely than many other voluntary sector organisations to provide the glue that might stick our fractured society together and help create stronger communities.