Meet the Clydesdale. The Clydesdale breed once almost faced extinction. Even though there is little practical use for heavy horses today because their muscle power has been replaced by machinery, breeders and enthusiasts have ensured that the breed is increasing, rather diminishing in numbers.
1 Over the three decades, the twin birth rate rose by 76 percent, from 18.9 to 33.2 per 1,000 births (or from 1.9 percent to 3.3 percent of all births) (Figure 1). 2  Increases in the twin birth rate averaged more than 2 percent a year from 1980 through 2004 (peaking at more than 4 percent from 1995 to 1998).
The National Vital Statistics Report for 2009 reports that 60% of twins were born preterm (less than 37 completed weeks of gestation) and 11.4% were considered very preterm (less than 32 completed weeks of gestation). There's no way to know exactly when your babies will be born.