Proper Traffic Variety 2/22/21 1.40

2/22/21 changelog:
-Fixed semi spawn rates
-Tweaked some vehicle spawn rates for accuracy (Ford F-350, Lincoln Navigator, Ford Mustang GT, and Hyundai Santa Fe Sport)
-Tweaked overall spawn rates

Features include:
- Semi-spawn decreased considerably.
- Vastly reduced the spawning of the police.
- Vastly reduced spawning of buses.
- Vehicles not sold spawned in the United States.
- Unrealized vehicles not spawned by fleet (some fire trucks, CHP Charger 2012, etc.).
- Outdated non-spawn fleet vehicles (MCI MC-12, NHP Crown Victoria, etc.).
- As stated previously, every spawning ratio is based on empirical data, which at least illustrates the car culture of every state somewhat accurately. California, for example, has a larger predominance of electric vehicles while other countries have increased pickups.