<#setting number_format="computer"> <#assign maxDate=0> <#list taxa as taxon> <#if taxon.date?number gt maxDate> <#assign maxDate=taxon.date?number> <#assign cutOff=maxDate-2019.75> <#-- old max date - cutoff --> <#assign gridPoints=((cutOff)*52)?round> <#-- assuming exactly 52 weeks a year --> <#list taxa as taxon> ${tree} ${tree}