By Rieva Lesonsky

We’ve long speculated about Millennials. How many of them are there? Are they really that different from other Americans? How can we best reach them?

Well, now we have some answers. A few months ago the U.S. Census Bureau announced Millennials are the biggest American generation ever. There are 83.1 million of them, aged 15 to 33 (meaning they were born between 1982 and 2000).

Millennials (also know as Gen Y) are quite diverse, both in the age range I just mentioned and in ethnicity. In fact, more than 44 percent of Millennials are part of a minority group.

Since many Millennials are still quite young (teenagers) or not financially secure (college students or just starting jobs), it might be smarter for your business to target older Millennials—especially since they’re in growth mode. The CDC’s (Centers for Disease Control and Prevention) National Center for Health Statistics reports the birth rate rose last year to 3,985,824—closing in on the “magical” 4 million mark, signifying an official baby boom year. The good news for many entrepreneurs (especially if you sell baby products or clothing or offer services for kids and parents) is this is the first rise in the number of births in the U.S. in seven years.

Expect these new Millennial parents to buy more. According to Mintel’s Online Shopping US 2015 while 69 percent of American adults shop online at least once a month, and 33 percent shop online weekly, the demographic who buys the most online is parents. And in fact, the report says the more children under 18 consumers have, the more they buy online. Forty percent of online shoppers with one child buy something online weekly, as do 56 percent of those with two kids and 66 percent of those with three children. In contrast, only 23 percent of consumers who don’t have kids at home make weekly online purchases.

And according to a survey from First Insight reported in Venture Beat, if you’re interested in selling products to Millennials the best way to reach them is via email. More than 40 percent of Millennials said they prefer email over social media (5 percent) and texts (2 percent).