A recent study indicates that Cold Jupiters similar to Saturn and Jupiter greatly outnumber Hot Jupiters. The authors studied 18 years worth of data to find long-period exoplanets, that is planets far from their host star.
Cold Jupiters, being farther from their host star, have longer periods than Hot Jupiters. Therefore, they need to be observed over a longer time frame to see multiple transits. ETs would need to observe the Sun for 12 years before seeing two transits of Jupiter, and that still wouldn't be enough to confirm its presence.
Planets that are further out also induce smaller variations in the velocity of their host star, so the spectrum of the star is shifted by a smaller amount. Therefore higher resolution spectrographs are needed to detect Cold Jupiters using the radial velocity method.
Finding more Warm and Hot Jupiters at the beginning of the era of exoplanetary discovery was an observational bias due to the limits of the instrumentation available at the time, and the amount of time needed to find long-period exoplanets.