  The debiased absolute-magnitude and orbit distributions as well as source
regions for near-Earth objects (NEOs) provide a fundamental frame of reference
for studies of individual NEOs and more complex population-level questions. We
present a new four-dimensional model of the NEO population that describes
debiased steady-state distributions of semimajor axis, eccentricity,
inclination, and absolute magnitude $H$ in the range $17<H<25$. The modeling
approach improves upon the methodology originally developed by Bottke et al.
(2000; Science 288, 2190-2194) in that it is, for example, based on more
realistic orbit distributions and uses source-specific absolute-magnitude
distributions that allow for a power-law slope that varies with $H$. We divide
the main asteroid belt into six different entrance routes or regions (ER) to
the NEO region: the $\nu_6$, 3:1J, 5:2J and 2:1J resonance complexes as well as
Hungarias and Phocaeas. In addition we include the Jupiter-family comets as the
primary cometary source of NEOs. We calibrate the model against NEO detections
by Catalina Sky Surveys' stations 703 and G96 during 2005-2012, and utilize the
complementary nature of these two systems to quantify the systematic
uncertainties associated to the resulting model. The most important ERs are the
$\nu_6$ and 3:1J resonance complexes with JFCs contributing a few percent of
NEOs on average. We predict that there are $962^{+52}_{-56}$
($802^{+48}_{-42}\times10^3$) NEOs with $H<17.75$ ($H<25$) and these numbers
are in agreement with the most recent estimates found in the literature (the
uncertainty estimates only account for the random component).
