The current situation in studies of lifetimes of excited rovibronic levels for the H_2, D_2, T_2, HD, HT, and DT molecules is analyzed. All measured lifetime values (792 entries for 618 different vibro-rotational levels of 33 electronic states) reported in 61 publications before April 2015, are compiled and listed in tabular format together with an annotated bibliography. Experimental data are only available for the H_2, HD and D_2 molecules. The data collected in the present work show fragmentariness of experimental data. For the vast majority of the levels, the lifetime values were reported in one paper only, and up to now are without independent experimental verification. A complete bibliography of publications concerning semi-empirical determination and non-empirical calculations of the lifetimes is presented. Numerical results obtained in the framework of these two approaches are listed only in cases when experimental data are available. For more than half of the levels, the differences between measured