Use the data in the table to model the population of the world in to 20th century by a cubic function. Then use your model to estimate the population in the year 1925.

**Year** | **Population (millions)** |

1900 | 1650 |

1910 | 1750 |

1920 | 1860 |

1930 | 2070 |

1940 | 2300 |

1950 | 2520 |

1960 | 3020 |

1970 | 3700 |

1980 | 4450 |

1990 | 5300 |

1996 | 5770 |

Using a graphing calculator to plot the points and do a cubic regression, I get the equation y=.00233x

^{3} - 13.065x

^{2} + 24463.108x - 15265793.873, which matches with the answer in the back of the book. But when I plug in 1925 for x into the equation, I get 32,352.933, which doesn't make since when looking at the table. The answer in the back of the book is 1922 million, which makes more sense because this is a suitable answer since it is between 1750 and 1860 (the values that correspond to years 1910 and 1920). I'm probably missing something very simple. How do I get 1922 million?