If you start counting shemitah cycles at the beginning of creation, and continue them all the way to the year 8000, then you will find that every 50th year is a Yovel (jubilee) and every year before that is a shemtiah year.
There are two general schools of thought on the counting, a 49 year cycle and a 50 year cycle. In the 49 they consider counting 7 weeks of years and the year AFTER 49 is ALSO the first year of the next counting cycle. It is possible, but not likely IMHO because then the 1000 year day will not be evenly divided into Yovel cycles until the year 49,000.
The 50 year cycle says there are 7 weeks of years, the next year (50th) is NOT counted as the first year of the next cycle, the first year is the 51st year. This seems to me to be much more plausible since the shemitah (49th year) is a land rest year of no planting, and the 50th year many people would be moving back to their land after the beginning of the year. IF that were the case they would not have any barley or wheat since it must be sowed before the winter of the 49th year to grow in the 50th year. And they would not have grain harvest for Yom ha Biqurim and shavout. There are many plants to plant in the fall for a spring harvest. So it is more likely the process was, shemitah land rest no planting, Yovel return to their land and work it into shape and begin planting what they can. Year 1 of next shemitah the full cycle of harvest and planting begins.
A 50 year cycle also puts every 50, 100, 150, 200, etc as a Yovel and thus the thousand year "days" would all be Yovels
Incidently, IF it is a 50 year cycle AND if Jesus/Yeshua died on year 30 (on the 80th Yovel), then 2030 would obviously be 40 cycles later the 120th Yovel, which would also be the 6000th year of creation. The fact that it works that way IF and only IF it is a 50 year cycle, the 49 year cycle just doesnt work.
What about prophetically, Moses was 80 when he began to set the captives of Israel . 80 seems to be connected to a Messianic number. Moses died when he was 120 and Joshua/Yehoshua took over and led the israelites into the promised land.
If Jesus/Yeshua arrived on the 80th Yovel to begin setting us free, and he returns on the 120th Yovel to take his people into the promised land, then it would fullfil the shadow picture of Moses and Joshua/Yehoshua.