Right behind Christmas and Valentine’s Day, Mother’s Day is one of the biggest spending holidays in North America – a trend that is increasing over time. According surveys conducted by National Retail Federation (NRF), the amount consumers expect to spend on their mothers on the second weekend in May has increased from an average of $97.37 in 2003 to $152.52 in 2013; even after controlling for inflation, that is a 20% spending increase in just ten years.

That evidence would, no doubt, displease Anna Marie Jarvis who in 1907 started the Mother’s Day tradition with a simple suggestion that every year children write their mothers a note showing their appreciation. She perused the idea further until 1914, when President Wilson declared the day a national holiday. From that point onward, as far as Anna Marie Jarvis was concerned, it was all downhill; the holiday became widely commercialized early in the 1920s when hand written thank you notes were replaced with purchased cards and gifts.

It would easy to interpret the spending increases in recent decades as further evidence of commercialization of the holiday, but there is another explanation for why spending is increasing over time, and that is because men and women in their 30s, 40s, and 50s do not, in general, give their mothers homemade crafts for Mother’s Day.

Only a small fraction of Mother’s Day gift giving is between very young children and their mothers, and that fraction is falling quickly as we transition from a younger to an older population and as more young adults are choosing not to have children of their own.

Older children continue to show appreciation to their mothers – according to the NRF 65% of adults plan to buy their mother a gift this year – and, as adults with higher incomes, they tend to buy more expensive gifts.

In the first ten years of this century, the share of the population over the age of 45 has increased nearly 5 percentage points and over 70% of adults 45 to 50 years old will be purchasing their mother a gift this year.

Over the same period the share of American households with children under the age of eighteen fell from 48% to 45%, as a result the share of gifts that are of the homemade craft / breakfast in bed type that we are all nostalgic for is reducing simply because there are fewer of those families.

This increase in the age of both the givers, and receivers, of Mother’s Day gifts also might explain why mom is now more likely to be given electronics and books for Mother’s Day than she was ten years ago, and why the biggest increases in spending has been on items like jewelry and spa treatments.

Just as surely as we know that billions of dollars will be spend this weekend to thank mothers for all that they do, millions of small children will be returning home from school today with glitter glued to their fingers as they work to give their mother the perfect gift.

Me, I have a whole box of homemade gifts accumulated over the years that I absolutely cherish, but this year I am looking forward to a leisurely champagne brunch with my, almost adult, children. I don’t believe that change in spending behavior is a fundamental change in the way we view holiday; it’s simply a change in the demographics of my household and, happily for everyone, an increase in the incomes of my children.

This post originally appeared on my blog at Psychology Today.