At NASA Goddard, they run climate models on our supercomputer and they are mostly in Fortran. I asked one of the developers once and he said the bulk of it was

At NASA Goddard, they run climate models on our supercomputer and they are mostly in Fortran. I asked one of the developers once and he said the bulk of it was in Fortran 90/95. But there is still a lot of Fortran 77 code around, particularly in well-debugged libraries. This developer wanted to use a more modern dialect and take advantage of some of the new features, like object orientation, but it was hard to get the scientists to learn the new features. That's a big part of why Fortran endures, it's simple inertia. During development of the original ANSI standard for C, the Cray rep and others wanted to add features that would enable C to kill Fortran. This meant adding complex numbers (which happened in C99 and was made optional in C11), and doing something about unrestricted pointers. The latter lead to the noalias fiasco, but ultimately we got strict, which accomplishes the same goal.