In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force. Thus string theory is a theory of quantum gravity.
Their average web application development cost is around $500K and their staff or contractors' salary is in the six figure plus range. Their proposals are usually based on a lot of fluff with the development rate ranging from $400 - $800 per hour. These types of companies focus on custom development.
It needs to be pointed out that the Mobile Apps Developer salary figure on the graph represents an average compensation for mobile app development. An average salary for a Lead Mobile Application Developer is higher and in 2016 it is $138k a year. US IT Average Annual Salaries in 2016, in thousands.