Before revision:   We empirically evaluate the proposed approach on real-world search query data and show that it outperforms existing approaches by one to two orders of magnitude in terms of its average (per element) estimation error and by 45-90\% in terms of its expected magnitude of estimation error.
After revision:  We empirically evaluate the proposed approach both on synthetic datasets and on real-world search query data and show that it outperforms existing approaches by one to two orders of magnitude in terms of its average (per element) estimation error and by 45-90\% in terms of its expected magnitude of estimation error.