References year-to-date time periods.
A summation of values from the beginning of a year to the present.
If a three-year model, 2004-2006, is in quarters:
@avg(v1040(-2Q), @ytd)
averages the year-to-date Cost of Goods Sold value from the prior two quarters. In the first quarter of 2006, the sums 1Q2000, 2Q2000, and 3Q2000, and divides by three.