Adjust Calculation Of Spend Ratio To Use Paired Data As Priority

[wendyrogers]

Currently Spend Ratio is based on whichever is the greatest result from the following calculations:

2014 IATI Spend / 2014 Reference Spend
2015 IATI Spend / 2015 Reference Spend
2015 IATI Spend / 2014 Reference Spend
2015 IATI Spend / 2015 Official Forecast

However, experience has demonstrated that the calculation

2015 IATI Spend / 2014 Reference Spend

should only be done when none of the other matching pairs of data are available. This is because:

a) if a complete pair of data (eg 2014 IATI Spend & 2014 Reference Spend) is available then it makes sense that the results of that calculation is used as the actual Spend ratio score
b) Use of 2015 IATI Spend / 2014 Reference Spend can benefit publishers who are currently publishing cumulative rather than annualised transactions

[dalepotter]

This issue is a duplicate of #375 (comment)

Will therefore close this issue.