change in performance calculation method

I have changed the performance calculation method to more accurately represent the performance of the stockgrumble portfolio.

The performance of individual stocks is now compared to the performance of the index based on the purchase date of the stock, tracked against current index price, and averaged over the sample.

No allowance is made for dividends, as I would have to give the index an average dividend rate.
I will look at this to see if it can be done in a fair way.

Performance
Code	Company	Buy date	buy price	current	profit loss	all ords performance adjusted to purchase date	all ords at time of purchase	Sell Date	Sell price
EPW	ERM Power Ltd	21/05/2014	$1.91	$1.92	0.5%	3.8%	5,401	22/8/2014	$1.92
CRZ	Caresales.com	23/05/2014	$10.53	$10.67	1.3%	3.8%	5,403
CCL	Coca Cola Amitel	26/05/2014	$9.69	$9.16	-5.5%	2.1%	5,490	22/8/2014	$9.16
SEA	Sundance energy	26/05/2014	$1.04	$1.34	29.5%	2.1%	5,490
WTF	Wotif.com	28/05/2014	$2.42	$3.33	37.6%	1.9%	5,506	11/7/2014	$3.34
REA	Realestate.com	28/05/2014	$44.19	$46.80	5.9%	1.9%	5,506
SUL	Supercheap auto	7/07/2014	$9.16	$9.15	-0.1%	1.9%	5,506
TRS	The Reject Shop	7/07/2014	$9.66	$9.80	1.4%	1.9%	5,506
CSL	CSL Limited	15/07/2014	$68.55	$73.20	6.8%	2.1%	5,495
CTD	Corporate Travel Man	15/07/2014	$6.55	$7.53	15.0%	2.1%	5,495
FLT	Flight Centre	15/07/2014	$45.84	$47.25	3.1%	2.1%	5,495
SEA	Sundance energy	31/07/2014	$1.34	$1.34	0.0%	-0.3%	5,623
BRG	Breville Group	27/08/2014	$7.24	$7.95	9.8%	-0.7%	5,648
BSL	Bluescope Steel	27/08/2014	$5.42	$5.58	3.0%	-0.7%	5,648
AGI	Ainsworth gaming	3/09/2014	$3.41	$3.40	-0.3%	-0.8%	5,654
							5608	all ords today
		Stockgrumble performance			7.2%	1.5%	all ords performance