The Disagreement Between Local Measurements and the Universe

The universe is expanding at a constant rate like 73 kilometers per second per megaparsec but overall because the whole universe is happening everywhere are you saying that this expansion is accelerating? We think it's a constant in space we think everywhere in the universe has the same expansion rate. As the universe gets less dense this number decreases but it is a number that we can measure and 70 kilometers per second sounds a lot so every second a chunk of space that's 3 million light years long gets bigger by 70 kilometers. Over very very long distances it does add up because there are a lot of megaparSecs in the universe.