Due to engine failures in qualifying he started 10th once and last 2, as a result of those failures they had to take engine penalties, that means starting from the back again in Spa. He then had the failure in Malaysia, that is 5 races, before counting Bottas dive bombing Hamilton which hit him down to 9th and ended up 30 seconds behind Rosberg in 3rd with zero chance to win. Then on top of that Rosberg hit Hamilton twice.
So there are at least 6 races(including the Spain contact but not Austria because despite Rosberg cheating it worked out for Hamilton) Hamilton was denied any chance at all to win. Take points unfairly off a driver in 6 races in a season and the other driver... effectively one (that weren't his own fault, Austria and Spain) with Vettel hitting him in Malaysia and the only other competitive driver(due to car) will have a monumental advantage.