Study of code share practices in science
This study is more qualitative than quantitative but might provide you with some more information about the scientific software space.

James Howison, Ewa Deelman, Michael J. McLennan, Rafael Ferreira da Silva, James D. Herbsleb; Understanding the scientific software ecosystem and its impact: Current and future measures. Res Eval 2015; 24 (4): 454-470. doi: 10.1093/reseval/rvv014