Income from actively participated LLC's treated as partnerships are subject to self-employment tax if reported correctly. On the K-1, there is a box under Part II if the taxpayer is a General Partner or LLC member-manager (Box G). If you answer that question in TurboTax correctly, TurboTax will generate a Schedule SE for the taxpayer to pay self-employment tax. SE tax is 15.3% of self-employment income.
I can only assume your wife did not pay any self-employment tax and that's the reason her SSA annual statement doesn't show her income from the LLC. If your wife did pay SE taxes for all those years, then contact SSA ASAP and get the error corrected. SSA will probably need her Schedules SE for each of the last ten years. I don't recall ever seeing SSA making such errors though.
