I'm extremely pressed for time at this second as I'm about to head out the front door, but the overall rate of mortality was 14.5% for the entirety of the transatlantic slave trade. There were considerable variations from year to year and between different national carriers, however.

This is a table showing the mortality rate by half century throughout the history of the transatlantic trade for different carriers; the name of the nation denotes the flag of the ship. At the dawn of the slave trade almost one in three slaves being taken out of Africa on Portugese and Spanish vessels die before they reach the New World; though there is a pattern of decline, mortality begins to increase again in the final years of the trade. By the time of its abolition, Britain's mortality rates have dropped from 29% to just 11%, reflective of a concerted (but ineffective) effort to 'Humanise' the condition of slavery on the one hand and to bring as many slaves into the Caribbean as possible before abolition on the other. Across the period, it ends up being Portuguese and French ships that have the lowest mortality rates, but there is not much between them. One of the biggest variations comes in 1701 - 1750, when Portuguese mortality is as low as 12% but Danish mortality as high as 28%. These are figures sourced from the Transatlantic Slave Trade Database, which has estimated figures for how many people left Africa and how many arrived in the New World, allowing us to reasonably gauge the rate of mortality onboard. So the vast majority of people taken out of Africa would in fact make it alive to the New World, but the death rate is still horrifically high - millions of people perished making the crossing from 1500 to 1866.

I'm afraid I can't speak to the mortality rate for slave ship crews off the top of my head. I am, however, very busy at the moment; I can address any follow up questions or requests for elaboration later, however.