Did the SNP break AMS?

Many Nats quite reasonably point out how some commentators are now considering the idea of electoral reform at Holyrood following the unprecedented SNP majority, is this really much different to the majority commanded by Labour and the Lib Dems in from 1999-2007?

	1999 (Lib/Lab)	2003 (Lib/Lab)	2011 (SNP)
Constituency	38.8 + 14.1 = 52.9%	34.6 + 15.3 = 49.9%	45.5%
List	33.3 + 12.4 = 45.7%	29.3 + 11.8 = 41.1%	44%
Combined	49.3%	45.5%	44.75%

 Looking at the majority Governments we've had previously we can see that they have all commanded less than 50% of the popular vote, although the SNP has a fractionally lower share than the 2003 Labour-Liberal Democrat coalition. 

For an essay I had to work out how proportional a result different electoral systems produce. I quickly added in a rough score for the 2011 Scottish Election and as we can see it would have appeared to have risen to a devolution high. (I used the simplest method, there are other variants to this.)

Deviation from Proportionality (DV)
2011	9.7
2007	6.35
2003	9.35
1999	5.5

In summary the SNP did not 'break' AMS they simply managed to get a higher percentage of the vote than any party before them. This thanks to the bias towards large parties, at the expense of the small, pushed them over half the available seats.

EDIT: This post was written last year and meant to be longer..