Some say motherhood is a thankless job. But this Sunday, America's kids, husbands, and grandkids plan to spend billions upon billions of dollars thanking the moms in their lives.

Here, a few more of the numbers behind Mother's Day:

$20.7 billion
The amount Americans will spend this Mother's Day, according to the National Retail Federation's Mother's Day spending survey

85.4 million
Moms in the U.S., according to the latest stats from the United States Census Bureau 

The average amount American consumers will spend on mom for Mother's Day 2013

The average spending last year. This year's figure is an 11 percent increase. 

Mother's Day's ranking, after Christmas and Valentine's Day, in terms of the amount of money spent by U.S. consumers

Father's Day's ranking

Percent of buyers who plan to purchase electronics as Mother's Day gifts — the highest percentage in history 

$2.3 billion
Amount expected to be spent on electronics for Mother's Day, up from last year's $1.6 billion 

$2.3 billion
Amount expected to be spent on flowers this Mother's Day

Florist establishments nationwide in 2010, according to New York Citizen One

Employees at floral shops across the U.S

Percent of Americans who will buy their gifts online this year

Percent of Americans who bought Mother's Day gifts online last year

Percent of shoppers who will buy Mother's Day gifts at discount stores

Percent of moms who would prefer to receive something homemade

Percent of daughters who plan to give something homemade 

Percent of sons who plan to give something homemade

Sources: Business PunditCensus, Credit DonkeyNational Retail Federation, New York Citizen One