For example, if the parties that didn't make it to Parliament received 6 per cent of the vote, and the parties that did received 94 per cent, then a single party or combination of parties would need just over 47 per cent to get a majority to govern.
Greens leader James Shaw is in a fight for his party's political life. Right now the Greens primary concern is survival, not whether it will be part of Government.
The Greens were kept out of Helen Clark's 2005 Government at the insistence of New Zealand First leader Winston Peters.
Helen Clark herself kept them out of Government in 2002 after relations soured during the campaign over genetic modification.
That was the first minority government under MMP - meaning it didn't have enough votes to govern on its own. But it had the stability to govern because it was guaranteed support on confidence and supply votes during the term by Peter Dunne's United Future, which opted to have no ministerial posts.
But it has been the 2005 model of government which has endured and which National has used for the past three terms, also as a minority government as Labour was.
It was originally seen as a challenge to the concept of collective Cabinet responsibility because it gave leaders of parties supporting the minority government senior ministerial positions but outside of Cabinet.
Ostensibly it may have been devised to help Peters to argue that he had kept his 2005 promise not to be part of a government.
But it has had bigger benefits.
It has given support parties a stake in government with ministerial posts but specifically allowed them to criticise their senior partner in areas outside their responsibility.
It has required the minority governing party to consult its support parties on all legislation and annual Budgets, allowing the support parties to come up with new initiatives outside the parameters of the initial confidence and supply agreements.
It has also allowed the large party to sign up disparate parties to work with the single large party of government and not necessarily have to work with each other in a coalition.
For example Act and the Maori Party happily co-existed despite Act wanting to get rid of the Maori seats, because their relationship has been with National, not each other.
National also had the support of United Future, so it has simultaneously managed three support relationships - although it has never required the support of the Maori Party.
Winston Peters was part of a majority coalition with National in 1996 and supported a minority Labour Government in 2005.
The expectation is that if his party was needed this time, it would be part of a coalition inside Cabinet. His party would be a lot bigger than the small parties which have supported National, and the larger share of ministerial posts would require it to be in the engine room of government, not on the periphery.
