I'll take Moffat's approach over coming back to modern london every other episode during RTD's reign.
Present-Day London appeared in:
Series One:
1.01, "Rose. 1.02, "The End of the World" (briefly in coda). 1.04, "Aliens of London." 1.05, "World War Three." 1.13, "The Parting of the Ways" (briefly in sub-plot).
Major Appearances: 23% of episodes.
Series Two:
2.00, "The Christmas Invasion." 2.01, "New Earth" (briefly in teaser). 2.03, "School Reunion." 2.05, "Rise of the Cybermen" (Alternate Universe London). 2.06, "The Age of Steel" (Alternate Universe London, and then briefly in coda). 2.10, "Love & Monsters." 2.11, "Fear Her" (technically near-future London). 2.12, "Army of Ghosts." 2.13, "Doomsday."
Major Appearances: 42.85% of episodes if we exclude Pete's World. 57.14% of episodes if we include Pete's World.
Series Three:
3.00, "The Runaway Bride." 3.01, "Smith and Jones." 3.06, "The Lazarus Experiment." 3.07, "42" (briefly, in sub-plot). 3.10, "Blink." 3.12, "The Sound of Drums." 3.13, "Last of the Time Lords" (briefly, in coda).
Major Appearances: 35.71% of episodes.
4.00, "Voyage of the Damned" (briefly, in sub-plot). 4.01, "Partners in Crime." 4.04, "The Sontaran Stratagem." 4.05, "The Poison Sky." 4.06, "The Doctor's Daughter" (briefly, in coda). 4.11, "Turn Left" (technically alternate timeline). 4.12, "The Stolen Earth." 4.13, "Journey's End." 4.15, "Planet of the Dead." 4.17, "The End of Time, Part One." 4.18, "The End of Time, Part Two."
Major Appearances: 50% of episodes.
Total Number for All Seasons: 47.27% of all RTD-era episodes.
You're right, modern-day London does appear more often in the RTD era than I'd thought.