Retrograde periods for Mercury, Venus, Mars, Jupiter and Saturn. Rahu and Ketu are always retrograde by convention.
1 retrograde period in 2018
124 days in Tula
3 retrograde periods in 2018
23 days in Meena
24 days in Karka
20 days in Vrishchika
1 retrograde period in 2018
141 days in Dhanu
1 retrograde period in 2018
62 days in Makara
1 retrograde period in 2018
42 days in Tula
Rahu and Ketu are the lunar nodes and are always Vakri (retrograde). They move backwards through the zodiac at roughly 1.5° per month and change Rashi only once every ~18 months.