sql server-percentage calculation
This is a great example of how the Window Functions can be used. Based on your data, I'm assuming you want to do this for every unique LINE_NO. I'll leave it to you to format the percentage column.

SELECT      LINE_NO,
            E_FIELD,
            F_FIELD,
            G_FIELD,
            HSA_STATUS,
            FAMILY,
            CACHE_FAMILY,
            COUNT(*) AS CT,
            COUNT(*) / SUM(COUNT(*) * 1.0) OVER (PARTITION BY LINE_NO)

FROM        TX_HSA_SUMM

GROUP BY    LINE_NO,
            E_FIELD,
            F_FIELD,
            G_FIELD,
            HSA_STATUS,
            FAMILY,
            CACHE_FAMILY