To create your stat you need to add two new columns in the Holdem Cash Player Statistics section:
cnt_p_face_minsteal:*
sum(if[holdem_hand_player_statistics.flg_blind_def_opp AND holdem_hand_player_detail.val_p_raise_facing_pct < 30, 1, 0])
cnt_p_face_minsteal_action_fold:
sum(if[holdem_hand_player_statistics.flg_blind_def_opp AND holdem_hand_player_detail.val_p_raise_facing_pct < 30 and lookup_actions_p.action = 'F', 1, 0])
Put the latter over the former, multiply by 100 and you have your percentage. (For a more detailed account of custom stat creation, please see the Tutorial: Using Custom Statistics and Reports.)
*The reason 30% was used is that certain limits do not add up nicely in the small blind amount. In .1/.25 you would need it to be slightly higher as the blinds are a smaller percentage of the pot than, say, 1/2. Please note: this stat will not work for tables with antes, and you will need to recalculate the percentage value for ante tables.