what is the average value of a loyal customer (VLC)in a target market segment if the average purchase price is $50 per visit, the frequency of reprchases is 12 times per year, contribution mergin is 10%. and the average customer defection rate is 25%? if a continuous improvement goal is set of a 20% defection rate next year and 15% two years from now, what are the rvised VLCs over their average buying life?