Understanding Society User Support

Hello,

I am trying to look at participants' start date of their current job. In the Wave 12 questionnaire, it looks like "jbbgdat" was used, however I can't find this variable in my dataset or in the variable search tool. I looked at the jbbgd/m/y variables, but they have ~98% inapplicable responses. Was jbbgdat included in Wave 12 or any previous waves? Or is there a different variable I should be using to look at employment start dates?

Thanks!