Blackjack simulator for Probability of a dealer bust for each starting card

I came up with this solution to another exercise out of John Zelle's Programming book.

#bust.py --- Simulates multiple games of blackjack with each possible dealer starting card and estimates
#   the probability that the dealer will bust

import random

def intro():
pass

def takecard():
card = random.randint(1, 10)
has_ace = False
#Randomly choose if the 1 is an ace
if card == 1:
has_ace = random.choice([True, False])
return card, has_ace

def sim_one_game(starter):
#For simulating the ace
if starter == 12:
starter = 1
has_ace = True

total = starter

while total <= 17:
card, has_ace = takecard()
total += card

#Ace is valued at 11 when it would produce a stopping total
if has_ace == True and total + 10 >= 17 and total + 10 <= 21:
total += 10

def sim_n_games(starter, game_count):
busts = 0
for i in range(game_count):
score = sim_one_game(starter)
if score > 21:
busts += 1
return busts

def sim_each_card(game_count):
bustsls = []
for i in range(1, 12):
bustsls.append(sim_n_games(i, game_count))

return bustsls

def output(bustsls, game_count):
print("Busts for Starting Card A: {} out of {} games. ({:0.1%})".format(bustsls, game_count, bustsls / game_count))
for card in range(1, 11):
print("Busts for Starting Card {}: {} out of {} games. ({:0.1%})".format(card, bustsls[card - 1], game_count, bustsls[card - 1] / game_count))

def main():
intro()
game_count = int(input("\nHow many rounds to simulate? "))
bustsls = sim_each_card(game_count)
output(bustsls, game_count)

if __name__ == "__main__": main()

It works pretty well, although when profiling it with 100.000 iterations it takes ~5 seconds to finish. When profiling I noticed that all the calls to random take up quite some time.

Anyone know a better way to solve this? Please note that I am a beginner and there are a lot of things I haven't learned anything about yet, but I'll read into all of your suggestions!