Auto loans over 60 months are not the best way to finance a car. And yet, 43.5% of new-car buyers in the third quarter of 2015 took out loans of 61 to 72 months, according to Experian.
DNA Tribes is correct that siblings can and do have very diverse DNA. Your autosomal DNA is a random subset of your mother's and father's DNA (50% from each parent). Two siblings will not have the same results for the same reason that they do not look exactly the same. They do not get the exact same 50% from each parent. Even identical twins don't have exactly the same DNA (only almost exactly the same).
If I get the question right, the answer is 6.25%, not 25% as the other answer says. Its easy to calculate. Siblings share 50% of DNA on average, it also doesn't deviate much from it as the shared HIR (half identical regions) are very long and can sometimes cover the whole chromosome. There are also the least amount of recombinations within one generation. Half siblings have half of that, as the name says, so 25%.