By way of a complete integration of the Friedmann equations , in terms of observables , it is shown that for the cosmological constant \Lambda > 0 there exist non-flat FLRW models for which the total density parameter \Omega remains \sim 1 throughout the entire history of the universe .
Further , it is shown that in a precise quantitative sense these models are not finely tuned .
When observations are brought to bear on the theory , and in particular the WMAP observations , they confirm that we live in just such a universe .
The conclusion holds when the classical notion of \Lambda is extended to dark energy .